Techniques for high performant virtual routing capabilities

ABSTRACT

Techniques are disclosed for providing high performant packets processing capabilities in a virtualized cloud environment that enhance the scalability and high availability of the packets processing infrastructure. In certain embodiments disclosed herein, the VNICs functionality performed by network virtualization devices (NVDs) is offloaded from the NVDs to a fleet of computers, referred to as VNIC-as-a-Service System (or VNICaaS system). VNICaaS system is configured to provide Virtual Network Interface Cards (VNICs)-related functionality or service for multiple compute instances belonging to multiple tenants or customers of the CSPI. The VNICaaS system is capable of hosting multiple VNICs to process and transmit traffic in a distributed virtualized cloud networks environment. A single VNIC executed by the VNICaaS system can be used to process packets received from multiple compute instances.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/175,573, filed Feb. 12, 2021, which claims the benefit of the filingdate of the following provisional applications: (1) U.S. ProvisionalApplication No. 63/131,699, filed on Dec. 29, 2020, and (2) U.S.Provisional Application No. 63/091,859, filed on Oct. 14, 2020. Theabove-referenced applications are incorporated herein by reference intheir entirety for all purposes.

BACKGROUND

The demand for cloud-based services continues to increase rapidly. Theterm cloud service is generally used to refer to a service that is madeavailable to users or customers on demand (e.g., via a subscriptionmodel) using systems and infrastructure (cloud infrastructure) providedby a cloud services provider. Typically, the servers and systems thatmake up the cloud service provider's infrastructure are separate fromthe customer's own on-premise servers and systems. Customers can thusavail themselves of cloud services provided by a cloud service providerwithout having to purchase separate hardware and software resources forthe services. There are various different types of cloud servicesincluding Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS),Infrastructure-as-a-Service (IaaS), and others.

To utilize cloud services, network traffic between a customer and acloud services provider is processed and transported over networkvirtualization device(s). Specifically, communication between customers'and service provider's virtual networks is handled by a virtualinterface hosted on the network virtualization device. The virtualinterface provides virtual networking for a physical networking resource(e.g., Network Interface Card (NIC)) to enable an ability to access,connect, secure, and modify cloud resources. Typically, a networkvirtualization device is attached to a computing instance (e.g., a cloudbased workstation) within a virtual network, and a virtual interface,Virtual Network Interface Card (VNIC), hosted on the networkvirtualization device manages communications of the computing instancewithin and outside the virtual network. The VNIC attached to thecomputing instance isn't horizontally scalable or highly available dueto bandwidth and processing limitations of the underlying networkvirtualization device. Accordingly, the VNIC isn't scalable forefficiently processing a large volume of network traffic nor capable ofprocessing traffic for multiple computing instances within the same ordifferent virtual networks. Building a high performant, scalable, andhighly available infrastructure to process network traffic is a complexand time-consuming task, especially when the infrastructure has to scaleacross multiple instances within one or more virtual networks.

SUMMARY

The present disclosure relates generally to techniques for providinghigh performant virtual routing capabilities, and more particularlyproviding scalability and high availability for processing networktraffic. Various embodiments are described herein, including methods,systems, non-transitory computer-readable storage media storingprograms, code, or instructions executable by one or more processors,and the like.

The disclosure relates to providing a technique for independentlyprocessing network traffic on a scalable and highly availabledistributed network infrastructure or a system defined as a VNIC as aService or VNICaaS system. An aspect of the present disclosure providesfor a method including: receiving, by a first host machine of a packetprocessing system comprising a plurality of host machines, a firstpacket originating from a first compute instance hosted by a source hostmachine that is different from the plurality of host machines, thepacket processing system being configured to provide functionality of aplurality of virtual network interface cards (VNICs), wherein the firstcompute instance is part of a first virtual cloud network (VCN);identifying, by the first host machine and from a plurality of workerthreads executed by the first host machine, a first worker thread forprocessing the first packet; identifying, by the first worker thread andbased upon information included in the first packet, a first VNIC fromthe plurality of VNICs to be used for processing the first packet;determining, by the first worker thread and based upon informationassociated with the first VNIC and destination information included inthe first packet, a first next-hop target to which the first packet isto be forwarded; and causing, by the first worker thread, the firstpacket to be forwarded to the first next-hop target to be forwarded to afirst destination.

Another aspect of the present disclosure provides for a computer system,comprising: one or more processors, and a non-transitorycomputer-readable storage medium containing instructions which, whenexecuted on the one or more processors, cause the one or more processorsto perform operations including: receiving, by a first host machine of apacket processing system comprising a plurality of host machines, afirst packet originating from a first compute instance hosted by asource host machine that is different from the plurality of hostmachines, the packet processing system being configured to providefunctionality of a plurality of virtual network interface cards (VNICs),wherein the first compute instance is part of a first virtual cloudnetwork (VCN); identifying, by the first host machine and from aplurality of worker threads executed by the first host machine, a firstworker thread for processing the first packet; identifying, by the firstworker thread and based upon information included in the first packet, afirst VNIC from the plurality of VNICs to be used for processing thefirst packet; determining, by the first worker thread and based uponinformation associated with the first VNIC and destination informationincluded in the first packet, a first next-hop target to which the firstpacket is to be forwarded; and causing, by the first worker thread, thefirst packet to be forwarded to the first next-hop target to beforwarded to a first destination.

Various embodiments are described herein, including methods, systems,non-transitory computer-readable storage media storing programs, code,or instructions executable by one or more processors, and the like.These illustrative embodiments are mentioned not to limit or define thedisclosure, but to provide examples to aid understanding thereof.Additional embodiments are discussed in the Detailed Description, andfurther description is provided there. For the sake of brevity anymention of “VNICaaS” or “system” later in this disclosure refersspecifically to a VNICaaS system, any mention of “service network” or“provider network” later in this disclosure refers specifically to“service provider's virtual cloud network,” and any mention of “customernetwork” or “customer virtual network” later in this disclosure refersspecifically to “customer VCN.”

BRIEF DESCRIPTION OF THE DRAWINGS

Features, embodiments, and advantages of the present disclosure arebetter understood when the following Detailed Description is read withreference to the accompanying drawings.

FIG. 1 is a high level diagram of a distributed environment showing avirtual or overlay cloud network hosted by a cloud service providerinfrastructure according to certain embodiments.

FIG. 2 depicts a simplified architectural diagram of the physicalcomponents in the physical network within cloud service providerinfrastructure (CSPI) according to certain embodiments.

FIG. 3 shows an example arrangement within CSPI where a host machine isconnected to multiple network virtualization devices (NVDs) according tocertain embodiments.

FIG. 4 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments.

FIG. 5 depicts a simplified block diagram of a physical network providedby a CSPI according to certain embodiments.

FIG. 6 is a simplified block diagram of a distributed virtualizedenvironment that may be hosted by CSPI provided by an IaaS cloud serviceprovider (CSP) and may include a VNICaaS system according to certainembodiments.

FIG. 7 is a simplified block diagram of a distributed environment thatincludes a VNICaaS system and builds upon the distributed environmentdepicted in FIG. 6 according to certain embodiments.

FIG. 8 depicts a simplified flowchart illustrating processing of packetsusing a VNICaaS system according to certain embodiments.

FIG. 9 is a simplified block diagram depicting components within aVNICaaS system according to certain embodiments.

FIG. 10 depicts distributed environment comprising a VNICaaS system andthe flow of packets for a particular use case between a customer'svirtual cloud network and a service provider's virtual cloud networkusing the VNICaaS system, according to certain embodiments.

FIGS. 11A-11C depict an example of encapsulation techniques that areused to communicate a network packet from a customer's compute instanceto a VNICaaS system according to certain embodiments.

FIGS. 12A-12C depict an example of encapsulation performed for aresponse packet to be communicated from a service compute instance to acustomer's compute instance according to certain embodiments.

FIG. 13 depicts a simplified flowchart depicting processing performedfor communicating a response packet using a VNICaaS system according tocertain embodiments.

FIG. 14 depicts a diagram of an exemplary VNICaaS system that processnetwork packets between plurality of compute instances within customer'sand service's virtual networks, according to at least one embodiment.

FIG. 15 depicts another simplified flowchart depicting processing ofpackets using a VNICaaS system according to certain embodiments.

FIG. 16 is a block diagram illustrating one pattern for implementing acloud infrastructure as a service system, according to at least oneembodiment.

FIG. 17 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 18 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 19 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 20 is a block diagram illustrating an example computer system,according to at least one embodiment.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, specificdetails are set forth in order to provide a thorough understanding ofcertain embodiments. However, it will be apparent that variousembodiments may be practiced without these specific details. The figuresand description are not intended to be restrictive. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any embodiment or design described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother embodiments or designs.

In an Infrastructure-as-a-Service (IaaS) model, a cloud service provider(CSP) provides infrastructure (referred to as cloud services providerinfrastructure or CSPI) that can be used to build one or more overlaynetworks, also referred to as virtual cloud networks (VCNs). The CSPIincludes compute, memory, and networking resources that provide theunderlying basis for creating one or more overlay or virtual cloudnetworks. Customers of CSPI can build their own virtual cloud networks(VCNs) using compute, memory, and networking resources provided by CSPI.A customer can deploy customer resources or workloads, such as computeinstances, on these customer VCNs. Compute instances can take the formof virtual machines, bare metal instances, and the like. These computeinstances may represent various customer workloads such as applications,load balancers, databases, and the like.

A compute instance participates in a VCN via a virtual network interfacecard (VNIC) that is configured for and associated or attached to thecompute instance. A VNIC is a logical representation of a physicalNetwork Interface Card (NIC). A VNIC provides an interface between anentity (e.g., a compute instance, a service) and a virtual network. AVNIC has one or more associated IP addresses. A VNIC associated with acompute instance enables the compute instance to be a part of a VCN andenables the compute instance to communicate (e.g., send and receivepackets) with endpoints that are in the same VCN and/or with endpointsoutside the VCN to which the compute instance belongs.

Compute instances may be hosted by host machines. For a compute instancehosted by a host machine, the VNIC functionality corresponding to theVNIC configured for that compute instance is executed by a networkvirtualization device (NVD), which is a physical device connected to thehost machine. An NVD is configured to implement various networkvirtualization functions to facilitate communication of packets to andfrom the compute instances. In certain embodiments, upon receiving apacket, an NVD is configured to execute a packet processing pipeline forprocessing the packet and determining how the packet is to be forwardedor routed, including encapsulation/decapsulation of packets, providingthe VNIC functionality, etc.

In specific architectures, for multiple compute instances hosted by ahost machine, the VNICs corresponding to the compute instances areexecuted by the NVD connected to the host machine. Since the processingand memory resources provided by an NVD are fixed, there is a limit onthe number of VNICs that can be supported by an NVD, which in turnlimits the number of compute instances hosted by a host machine.Further, as the number of VNICs executed by an NVD increases, itconstrains the bandwidth and resources available for each of the VNICsand thus the bandwidth and resources available for processing packetsoriginating from and received by the compute instances hosted by thehost machine. This limits the scalability of the architecture and limitsit to the underlying physical NVD resources.

The present disclosure describes a new highly available and scalablearchitecture for providing VNICs-related functionality. In certainimplementations, a portion of the VNICs functionality previouslyprovided by the NVDs is offloaded from the NVDs and provided instead bya centralized system whose resources (e.g., computer, memory, andnetworking resources) can be scaled as desired. In this architecture,the centralized system can host and execute VNICs for multiple computeinstances belonging to one or multiple customers or tenants of the CSPI.The centralized system comprises a fleet of computers that areconfigured to execute multiple VNICs and is a horizontally scalable. Incertain implementations, the functionality provided by the system isoffered as a service and the centralized system is thus referred to asVNIC-as-a-Service system or VNICaaS system.

The present disclosure describes techniques for providing highperformant packets processing capabilities in a virtualized cloudenvironment that enhance the scalability and high availability of thepackets processing infrastructure. In certain embodiments disclosedherein, the VNICs functionality performed by the NVDs is offloaded fromthe NVDs to a fleet of computers, referred to as VNIC-as-a-ServiceSystem (or VNICaaS system) that is configured to provide VNICs-relatedfunctionality or service for multiple compute instances belonging tomultiple tenants or customers of the CSPI. In certain implementations, asingle VNIC executed by the VNICaaS system can be used to processpackets received from multiple compute instances. This is different fromother architectures where there is a one-to one correspondence between acompute instance and a VNIC. A VNIC hosted by VNICaaS system can also beassociated with multiple VNICs corresponding to compute instances. Wherethese multiple compute instances are the intended destination endpointsof a packet processed by the VNICaaS system, one of the multipledestination endpoints may be selected by VNICaaS system for receivingthe packet. The functionalities provided by VNICaaS system thus enableVNICs and associated packet processing to be scaled and made highlyavailable for multiple compute instances from multiple tenants.

Example Architecture of Cloud Infrastructure

The term cloud service is generally used to refer to a service that ismade available by a cloud services provider (CSP) to users or customerson demand (e.g., via a subscription model) using systems andinfrastructure (cloud infrastructure) provided by the CSP. Typically,the servers and systems that make up the CSP's infrastructure areseparate from the customer's own on-premise servers and systems.Customers can thus avail themselves of cloud services provided by theCSP without having to purchase separate hardware and software resourcesfor the services. Cloud services are designed to provide a subscribingcustomer easy, scalable access to applications and computing resourceswithout the customer having to invest in procuring the infrastructurethat is used for providing the services.

There are several cloud service providers that offer various types ofcloud services. There are various different types or models of cloudservices including Software-as-a-Service (SaaS), Platform-as-a-Service(PaaS), Infrastructure-as-a-Service (IaaS), and others.

A customer can subscribe to one or more cloud services provided by aCSP. The customer can be any entity such as an individual, anorganization, an enterprise, and the like. When a customer subscribes toor registers for a service provided by a CSP, a tenancy or an account iscreated for that customer. The customer can then, via this account,access the subscribed-to one or more cloud resources associated with theaccount.

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing service. In an IaaS model, the CSP providesinfrastructure (referred to as cloud services provider infrastructure orCSPI) that can be used by customers to build their own customizablenetworks and deploy customer resources. The customer's resources andnetworks are thus hosted in a distributed environment by infrastructureprovided by a CSP. This is different from traditional computing, wherethe customer's resources and networks are hosted by infrastructureprovided by the customer.

The CSPI may comprise interconnected high-performance compute resourcesincluding various host machines, memory resources, and network resourcesthat form a physical network, which is also referred to as a substratenetwork or an underlay network. The resources in CSPI may be spreadacross one or more data centers that may be geographically spread acrossone or more geographical regions. Virtualization software may beexecuted by these physical resources to provide a virtualizeddistributed environment. The virtualization creates an overlay network(also known as a software-based network, a software-defined network, ora virtual network) over the physical network. The CSPI physical networkprovides the underlying basis for creating one or more overlay orvirtual networks on top of the physical network. The physical network(or substrate network or underlay network) comprises physical networkdevices such as physical switches, routers, computers and host machines,and the like. An overlay network is a logical (or virtual) network thatruns on top of a physical substrate network. A given physical networkcan support one or multiple overlay networks. Overlay networks typicallyuse encapsulation techniques to differentiate between traffic belongingto different overlay networks. A virtual or overlay network is alsoreferred to as a virtual cloud network (VCN). The virtual networks areimplemented using software virtualization technologies (e.g.,hypervisors, virtualization functions implemented by physical devicessuch as network virtualization devices (NVDs) (e.g., smartNICs),top-of-rack (TOR) switches, smart TORs that implement one or morefunctions performed by an NVD, and other mechanisms) to create layers ofnetwork abstraction that can be run on top of the physical network.Virtual networks can take on many forms, including peer-to-peernetworks, IP networks, and others. Virtual networks are typically eitherLayer-3 IP networks or Layer-2 VLANs. This method of virtual or overlaynetworking is often referred to as virtual or overlay Layer-3networking. Examples of protocols developed for virtual networks includeIP-in-IP (or Generic Routing Encapsulation (GRE)), Virtual ExtensibleLAN (VXLAN IETF RFC 7348), Virtual Private Networks (VPNs) (e.g., MPLSLayer-3 Virtual Private Networks (RFC 4364)), VMware's NSX, GENEVE(Generic Network Virtualization Encapsulation), and others.

For IaaS, the infrastructure (CSPI) provided by a CSP can be configuredto provide virtualized computing resources over a public network (e.g.,the Internet). In an IaaS model, a cloud computing services provider canhost the infrastructure components (e.g., servers, storage devices,network nodes (e.g., hardware), deployment software, platformvirtualization (e.g., a hypervisor layer), or the like). In some cases,an IaaS provider may also supply a variety of services to accompanythose infrastructure components (e.g., billing, monitoring, logging,security, load balancing and clustering, etc.). Thus, as these servicesmay be policy-driven, IaaS users may be able to implement policies todrive load balancing to maintain application availability andperformance. CSPI provides infrastructure and a set of complementarycloud services that enable customers to build and run a wide range ofapplications and services in a highly available hosted distributedenvironment. CSPI offers high-performance compute resources andcapabilities and storage capacity in a flexible virtual network that issecurely accessible from various networked locations such as from acustomer's on-premises network. When a customer subscribes to orregisters for an IaaS service provided by a CSP, the tenancy created forthat customer is a secure and isolated partition within the CSPI wherethe customer can create, organize, and administer their cloud resources.

Customers can build their own virtual networks using compute, memory,and networking resources provided by CSPI. One or more customerresources or workloads, such as compute instances, can be deployed onthese virtual networks. For example, a customer can use resourcesprovided by CSPI to build one or multiple customizable and privatevirtual network(s) referred to as virtual cloud networks (VCNs). Acustomer can deploy one or more customer resources, such as computeinstances, on a customer VCN. Compute instances can take the form ofvirtual machines, bare metal instances, and the like. The CSPI thusprovides infrastructure and a set of complementary cloud services thatenable customers to build and run a wide range of applications andservices in a highly available virtual hosted environment. The customerdoes not manage or control the underlying physical resources provided byCSPI but has control over operating systems, storage, and deployedapplications; and possibly limited control of select networkingcomponents (e.g., firewalls).

The CSP may provide a console that enables customers and networkadministrators to configure, access, and manage resources deployed inthe cloud using CSPI resources. In certain embodiments, the consoleprovides a web-based user interface that can be used to access andmanage CSPI. In some implementations, the console is a web-basedapplication provided by the CSP.

CSPI may support single-tenancy or multi-tenancy architectures. In asingle tenancy architecture, a software (e.g., an application, adatabase) or a hardware component (e.g., a host machine or a server)serves a single customer or tenant. In a multi-tenancy architecture, asoftware or a hardware component serves multiple customers or tenants.Thus, in a multi-tenancy architecture, CSPI resources are shared betweenmultiple customers or tenants. In a multi-tenancy situation, precautionsare taken and safeguards put in place within CSPI to ensure that eachtenant's data is isolated and remains invisible to other tenants.

In a physical network, a network endpoint (“endpoint”) refers to acomputing device or system that is connected to a physical network andcommunicates back and forth with the network to which it is connected. Anetwork endpoint in the physical network may be connected to a LocalArea Network (LAN), a Wide Area Network (WAN), or other type of physicalnetwork. Examples of traditional endpoints in a physical network includemodems, hubs, bridges, switches, routers, and other networking devices,physical computers (or host machines), and the like. Each physicaldevice in the physical network has a fixed network address that can beused to communicate with the device. This fixed network address can be aLayer-2 address (e.g., a MAC address), a fixed Layer-3 address (e.g., anIP address), and the like. In a virtualized environment or in a virtualnetwork, the endpoints can include various virtual endpoints such asvirtual machines that are hosted by components of the physical network(e.g., hosted by physical host machines). These endpoints in the virtualnetwork are addressed by overlay addresses such as overlay Layer-2addresses (e.g., overlay MAC addresses) and overlay Layer-3 addresses(e.g., overlay IP addresses). Network overlays enable flexibility byallowing network managers to move around the overlay addressesassociated with network endpoints using software management (e.g., viasoftware implementing a control plane for the virtual network).Accordingly, unlike in a physical network, in a virtual network, anoverlay address (e.g., an overlay IP address) can be moved from oneendpoint to another using network management software. Since the virtualnetwork is built on top of a physical network, communications betweencomponents in the virtual network involves both the virtual network andthe underlying physical network. In order to facilitate suchcommunications, the components of CSPI are configured to learn and storemappings that map overlay addresses in the virtual network to actualphysical addresses in the substrate network, and vice versa. Thesemappings are then used to facilitate the communications. Customertraffic is encapsulated to facilitate routing in the virtual network.

Accordingly, physical addresses (e.g., physical IP addresses) areassociated with components in physical networks and overlay addresses(e.g., overlay IP addresses) are associated with entities in virtual oroverlay networks. A physical IP address is an IP address associated witha physical device (e.g., a network device) in the substrate or physicalnetwork. For example, each NVD has an associated physical IP address. Anoverlay IP address is an overlay address associated with an entity in anoverlay network, such as with a compute instance in a customer's virtualcloud network (VCN). Two different customers or tenants, each with theirown private VCNs can potentially use the same overlay IP address intheir VCNs without any knowledge of each other. Both the physical IPaddresses and overlay IP addresses are types of real IP addresses. Theseare separate from virtual IP addresses. A virtual IP address istypically a single IP address that represents or maps to multiple realIP addresses. A virtual IP address provides a 1-to-many mapping betweenthe virtual IP address and multiple real IP addresses. For example, aload balancer may use a VIP to map to or represent multiple servers,each server having its own real IP address.

The cloud infrastructure or CSPI is physically hosted in one or moredata centers in one or more regions around the world. The CSPI mayinclude components in the physical or substrate network and virtualizedcomponents (e.g., virtual networks, compute instances, virtual machines,etc.) that are in a virtual network built on top of the physical networkcomponents. In certain embodiments, the CSPI is organized and hosted inrealms, regions and availability domains. A region is typically alocalized geographic area that contains one or more data centers.Regions are generally independent of each other and can be separated byvast distances, for example, across countries or even continents. Forexample, a first region may be in Australia, another one in Japan, yetanother one in India, and the like. CSPI resources are divided amongregions such that each region has its own independent subset of CSPIresources. Each region may provide a set of core infrastructure servicesand resources, such as, compute resources (e.g., bare metal servers,virtual machine, containers and related infrastructure, etc.); storageresources (e.g., block volume storage, file storage, object storage,archive storage); networking resources (e.g., virtual cloud networks(VCNs), load balancing resources, connections to on-premise networks),database resources; edge networking resources (e.g., DNS); and accessmanagement and monitoring resources, and others. Each region generallyhas multiple paths connecting it to other regions in the realm.

Generally, an application is deployed in a region (i.e., deployed oninfrastructure associated with that region) where it is most heavilyused, because using nearby resources is faster than using distantresources. Applications can also be deployed in different regions forvarious reasons, such as redundancy to mitigate the risk of region-wideevents such as large weather systems or earthquakes, to meet varyingrequirements for legal jurisdictions, tax domains, and other business orsocial criteria, and the like.

The data centers within a region can be further organized and subdividedinto availability domains (ADs). An availability domain may correspondto one or more data centers located within a region. A region can becomposed of one or more availability domains. In such a distributedenvironment, CSPI resources are either region-specific, such as avirtual cloud network (VCN), or availability domain-specific, such as acompute instance.

ADs within a region are isolated from each other, fault tolerant, andare configured such that they are very unlikely to fail simultaneously.This is achieved by the ADs not sharing critical infrastructureresources such as networking, physical cables, cable paths, cable entrypoints, etc., such that a failure at one AD within a region is unlikelyto impact the availability of the other ADs within the same region. TheADs within the same region may be connected to each other by a lowlatency, high bandwidth network, which makes it possible to providehigh-availability connectivity to other networks (e.g., the Internet,customers' on-premise networks, etc.) and to build replicated systems inmultiple ADs for both high-availability and disaster recovery. Cloudservices use multiple ADs to ensure high availability and to protectagainst resource failure. As the infrastructure provided by the IaaSprovider grows, more regions and ADs may be added with additionalcapacity. Traffic between availability domains is usually encrypted.

In certain embodiments, regions are grouped into realms. A realm is alogical collection of regions. Realms are isolated from each other anddo not share any data. Regions in the same realm may communicate witheach other, but regions in different realms cannot. A customer's tenancyor account with the CSP exists in a single realm and can be spreadacross one or more regions that belong to that realm. Typically, when acustomer subscribes to an IaaS service, a tenancy or account is createdfor that customer in the customer-specified region (referred to as the“home” region) within a realm. A customer can extend the customer'stenancy across one or more other regions within the realm. A customercannot access regions that are not in the realm where the customer'stenancy exists.

An IaaS provider can provide multiple realms, each realm catered to aparticular set of customers or users. For example, a commercial realmmay be provided for commercial customers. As another example, a realmmay be provided for a specific country for customers within thatcountry. As yet another example, a government realm may be provided fora government, and the like. For example, the government realm may becatered for a specific government and may have a heightened level ofsecurity than a commercial realm. For example, Oracle CloudInfrastructure (OCI) currently offers a realm for commercial regions andtwo realms (e.g., FedRAMP authorized and IL5 authorized) for governmentcloud regions.

In certain embodiments, an AD can be subdivided into one or more faultdomains. A fault domain is a grouping of infrastructure resources withinan AD to provide anti-affinity. Fault domains allow for the distributionof compute instances such that the instances are not on the samephysical hardware within a single AD. This is known as anti-affinity. Afault domain refers to a set of hardware components (computers,switches, and more) that share a single point of failure. A compute poolis logically divided up into fault domains. Due to this, a hardwarefailure or compute hardware maintenance event that affects one faultdomain does not affect instances in other fault domains. Depending onthe embodiment, the number of fault domains for each AD may vary. Forinstance, in certain embodiments each AD contains three fault domains. Afault domain acts as a logical data center within an AD.

When a customer subscribes to an IaaS service, resources from CSPI areprovisioned for the customer and associated with the customer's tenancy.The customer can use these provisioned resources to build privatenetworks and deploy resources on these networks. The customer networksthat are hosted in the cloud by the CSPI are referred to as virtualcloud networks (VCNs). A customer can set up one or more virtual cloudnetworks (VCNs) using CSPI resources allocated for the customer. A VCNis a virtual or software defined private network. The customer resourcesthat are deployed in the customer's VCN can include compute instances(e.g., virtual machines, bare-metal instances) and other resources.These compute instances may represent various customer workloads such asapplications, load balancers, databases, and the like. A computeinstance deployed on a VCN can communicate with public accessibleendpoints (“public endpoints”) over a public network such as theInternet, with other instances in the same VCN or other VCNs (e.g., thecustomer's other VCNs, or VCNs not belonging to the customer), with thecustomer's on-premise data centers or networks, and with serviceendpoints, and other types of endpoints.

The CSP may provide various services using the CSPI. In some instances,customers of CSPI may themselves act like service providers and provideservices using CSPI resources. A service provider may expose a serviceendpoint, which is characterized by identification information (e.g., anIP Address, a DNS name and port). A customer's resource (e.g., a computeinstance) can consume a particular service by accessing a serviceendpoint exposed by the service for that particular service. Theseservice endpoints are generally endpoints that are publicly accessibleby users using public IP addresses associated with the endpoints via apublic communication network such as the Internet. Network endpointsthat are publicly accessible are also sometimes referred to as publicendpoints.

In certain embodiments, a service provider may expose a service via anendpoint (sometimes referred to as a service endpoint) for the service.Customers of the service can then use this service endpoint to accessthe service. In certain implementations, a service endpoint provided fora service can be accessed by multiple customers that intend to consumethat service. In other implementations, a dedicated service endpoint maybe provided for a customer such that only that customer can access theservice using that dedicated service endpoint.

In certain embodiments, when a VCN is created, it is associated with aprivate overlay Classless Inter-Domain Routing (CIDR) address space,which is a range of private overlay IP addresses that are assigned tothe VCN (e.g., 10.0/16). A VCN includes associated subnets, routetables, and gateways. A VCN resides within a single region but can spanone or more or all of the region's availability domains. A gateway is avirtual interface that is configured for a VCN and enables communicationof traffic to and from the VCN to one or more endpoints outside the VCN.One or more different types of gateways may be configured for a VCN toenable communication to and from different types of endpoints.

A VCN can be subdivided into one or more sub-networks such as one ormore subnets. A subnet is thus a unit of configuration or a subdivisionthat can be created within a VCN. A VCN can have one or multiplesubnets. Each subnet within a VCN is associated with a contiguous rangeof overlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN.

Each compute instance is associated with a virtual network interfacecard (VNIC) that enables the compute instance to participate in a subnetof a VCN. A VNIC is a logical representation of physical NetworkInterface Card (NIC). In general, a VNIC is an interface between anentity (e.g., a compute instance, a service) and a virtual network. AVNIC exists in a subnet, has one or more associated IP addresses, andassociated security rules or policies. A VNIC is equivalent to a Layer-2port on a switch. A VNIC is attached to a compute instance and to asubnet within a VCN. A VNIC associated with a compute instance enablesthe compute instance to be a part of a subnet of a VCN and enables thecompute instance to communicate (e.g., send and receive packets) withendpoints that are on the same subnet as the compute instance, withendpoints in different subnets in the VCN, or with endpoints outside theVCN. The VNIC associated with a compute instance thus determines how thecompute instance connects with endpoints inside and outside the VCN. AVNIC for a compute instance is created and associated with that computeinstance when the compute instance is created and added to a subnetwithin a VCN. For a subnet comprising a set of compute instances, thesubnet contains the VNICs corresponding to the set of compute instances,each VNIC attached to a compute instance within the set of computerinstances.

Each compute instance is assigned a private overlay IP address via theVNIC associated with the compute instance. This private overlay IPaddress is assigned to the VNIC that is associated with the computeinstance when the compute instance is created and used for routingtraffic to and from the compute instance. All VNICs in a given subnetuse the same route table, security lists, and DHCP options. As describedabove, each subnet within a VCN is associated with a contiguous range ofoverlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN. For a VNIC on aparticular subnet of a VCN, the private overlay IP address that isassigned to the VNIC is an address from the contiguous range of overlayIP addresses allocated for the subnet.

In certain embodiments, a compute instance may optionally be assignedadditional overlay IP addresses in addition to the private overlay IPaddress, such as, for example, one or more public IP addresses if in apublic subnet. These multiple addresses are assigned either on the sameVNIC or over multiple VNICs that are associated with the computeinstance. Each instance however has a primary VNIC that is createdduring instance launch and is associated with the overlay private IPaddress assigned to the instance—this primary VNIC cannot be removed.Additional VNICs, referred to as secondary VNICs, can be added to anexisting instance in the same availability domain as the primary VNIC.All the VNICs are in the same availability domain as the instance. Asecondary VNIC can be in a subnet in the same VCN as the primary VNIC,or in a different subnet that is either in the same VCN or a differentone.

A compute instance may optionally be assigned a public IP address if itis in a public subnet. A subnet can be designated as either a publicsubnet or a private subnet at the time the subnet is created. A privatesubnet means that the resources (e.g., compute instances) and associatedVNICs in the subnet cannot have public overlay IP addresses. A publicsubnet means that the resources and associated VNICs in the subnet canhave public IP addresses. A customer can designate a subnet to existeither in a single availability domain or across multiple availabilitydomains in a region or realm.

As described above, a VCN may be subdivided into one or more subnets. Incertain embodiments, a Virtual Router (VR) configured for the VCN(referred to as the VCN VR or just VR) enables communications betweenthe subnets of the VCN. For a subnet within a VCN, the VR represents alogical gateway for that subnet that enables the subnet (i.e., thecompute instances on that subnet) to communicate with endpoints on othersubnets within the VCN, and with other endpoints outside the VCN. TheVCN VR is a logical entity that is configured to route traffic betweenVNICs in the VCN and virtual gateways (“gateways”) associated with theVCN. Gateways are further described below with respect to FIG. 1 . A VCNVR is a Layer-3/IP Layer concept. In one embodiment, there is one VCN VRfor a VCN where the VCN VR has potentially an unlimited number of portsaddressed by IP addresses, with one port for each subnet of the VCN. Inthis manner, the VCN VR has a different IP address for each subnet inthe VCN that the VCN VR is attached to. The VR is also connected to thevarious gateways configured for a VCN. In certain embodiments, aparticular overlay IP address from the overlay IP address range for asubnet is reserved for a port of the VCN VR for that subnet. Forexample, consider a VCN having two subnets with associated addressranges 10.0/16 and 10.1/16, respectively. For the first subnet withinthe VCN with address range 10.0/16, an address from this range isreserved for a port of the VCN VR for that subnet. In some instances,the first IP address from the range may be reserved for the VCN VR. Forexample, for the subnet with overlay IP address range 10.0/16, IPaddress 10.0.0.1 may be reserved for a port of the VCN VR for thatsubnet. For the second subnet within the same VCN with address range10.1/16, the VCN VR may have a port for that second subnet with IPaddress 10.1.0.1. The VCN VR has a different IP address for each of thesubnets in the VCN.

In some other embodiments, each subnet within a VCN may have its ownassociated VR that is addressable by the subnet using a reserved ordefault IP address associated with the VR. The reserved or default IPaddress may, for example, be the first IP address from the range of IPaddresses associated with that subnet. The VNICs in the subnet cancommunicate (e.g., send and receive packets) with the VR associated withthe subnet using this default or reserved IP address. In such anembodiment, the VR is the ingress/egress point for that subnet. The VRassociated with a subnet within the VCN can communicate with other VRsassociated with other subnets within the VCN. The VRs can alsocommunicate with gateways associated with the VCN. The VR function for asubnet is running on or executed by one or more NVDs executing VNICsfunctionality for VNICs in the subnet.

Route tables, security rules, and DHCP options may be configured for aVCN. Route tables are virtual route tables for the VCN and include rulesto route traffic from subnets within the VCN to destinations outside theVCN by way of gateways or specially configured instances. A VCN's routetables can be customized to control how packets are forwarded/routed toand from the VCN. DHCP options refers to configuration information thatis automatically provided to the instances when they boot up.

Security rules configured for a VCN represent overlay firewall rules forthe VCN. The security rules can include ingress and egress rules, andspecify the types of traffic (e.g., based upon protocol and port) thatis allowed in and out of the instances within the VCN. The customer canchoose whether a given rule is stateful or stateless. For instance, thecustomer can allow incoming SSH traffic from anywhere to a set ofinstances by setting up a stateful ingress rule with source CIDR0.0.0.0/0, and destination TCP port 22. Security rules can beimplemented using network security groups or security lists. A networksecurity group consists of a set of security rules that apply only tothe resources in that group. A security list, on the other hand,includes rules that apply to all the resources in any subnet that usesthe security list. A VCN may be provided with a default security listwith default security rules. DHCP options configured for a VCN provideconfiguration information that is automatically provided to theinstances in the VCN when the instances boot up.

In certain embodiments, the configuration information for a VCN isdetermined and stored by a VCN Control Plane. The configurationinformation for a VCN may include, for example, information about: theaddress range associated with the VCN, subnets within the VCN andassociated information, one or more VRs associated with the VCN, computeinstances in the VCN and associated VNICs, NVDs executing the variousvirtualization network functions (e.g., VNICs, VRs, gateways) associatedwith the VCN, state information for the VCN, and other VCN-relatedinformation. In certain embodiments, a VCN Distribution Servicepublishes the configuration information stored by the VCN Control Plane,or portions thereof, to the NVDs. The distributed information may beused to update information (e.g., forwarding tables, routing tables,etc.) stored and used by the NVDs to forward packets to and from thecompute instances in the VCN.

In certain embodiments, the creation of VCNs and subnets are handled bya VCN Control Plane (CP) and the launching of compute instances ishandled by a Compute Control Plane. The Compute Control Plane isresponsible for allocating the physical resources for the computeinstance and then calls the VCN Control Plane to create and attach VNICsto the compute instance. The VCN CP also sends VCN data mappings to theVCN data plane that is configured to perform packet forwarding androuting functions. In certain embodiments, the VCN CP provides adistribution service that is responsible for providing updates to theVCN data plane. Examples of a VCN Control Plane are also depicted inFIGS. 16, 17, 18, and 19 (see references 1616, 1716, 1816, and 1916) anddescribed below.

A customer may create one or more VCNs using resources hosted by CSPI. Acompute instance deployed on a customer VCN may communicate withdifferent endpoints. These endpoints can include endpoints that arehosted by CSPI and endpoints outside CSPI.

Various different architectures for implementing cloud-based serviceusing CSPI are depicted in FIGS. 1, 2, 3, 4, 5, 16, 17, 18, and 19 aredescribed below. FIG. 1 is a high level diagram of a distributedenvironment 100 showing an overlay or customer VCN hosted by CSPIaccording to certain embodiments. The distributed environment depictedin FIG. 1 includes multiple components in the overlay network.Distributed environment 100 depicted in FIG. 1 is merely an example andis not intended to unduly limit the scope of claimed embodiments. Manyvariations, alternatives, and modifications are possible. For example,in some implementations, the distributed environment depicted in FIG. 1may have more or fewer systems or components than those shown in FIG. 1, may combine two or more systems, or may have a different configurationor arrangement of systems.

As shown in the example depicted in FIG. 1 , distributed environment 100comprises CSPI 101 that provides services and resources that customerscan subscribe to and use to build their virtual cloud networks (VCNs).In certain embodiments, CSPI 101 offers IaaS services to subscribingcustomers. The data centers within CSPI 101 may be organized into one ormore regions. One example region “Region US” 102 is shown in FIG. 1 . Acustomer has configured a customer VCN 104 for region 102. The customermay deploy various compute instances on VCN 104, where the computeinstances may include virtual machines or bare metal instances. Examplesof instances include applications, database, load balancers, and thelike.

In the embodiment depicted in FIG. 1 , customer VCN 104 comprises twosubnets, namely, “Subnet-1” and “Subnet-2”, each subnet with its ownCIDR IP address range. In FIG. 1 , the overlay IP address range forSubnet-1 is 10.0/16 and the address range for Subnet-2 is 10.1/16. A VCNVirtual Router 105 represents a logical gateway for the VCN that enablescommunications between subnets of the VCN 104, and with other endpointsoutside the VCN. VCN VR 105 is configured to route traffic between VNICsin VCN 104 and gateways associated with VCN 104. VCN VR 105 provides aport for each subnet of VCN 104. For example, VR 105 may provide a portwith IP address 10.0.0.1 for Subnet-1 and a port with IP address10.1.0.1 for Subnet-2.

Multiple compute instances may be deployed on each subnet, where thecompute instances can be virtual machine instances, and/or bare metalinstances. The compute instances in a subnet may be hosted by one ormore host machines within CSPI 101. A compute instance participates in asubnet via a VNIC associated with the compute instance. For example, asshown in FIG. 1 , a compute instance C1 is part of Subnet-1 via a VNICassociated with the compute instance. Likewise, compute instance C2 ispart of Subnet-1 via a VNIC associated with C2. In a similar manner,multiple compute instances, which may be virtual machine instances orbare metal instances, may be part of Subnet-1. Via its associated VNIC,each compute instance is assigned a private overlay IP address and a MACaddress. For example, in FIG. 1 , compute instance C1 has an overlay IPaddress of 10.0.0.2 and a MAC address of M1, while compute instance C2has a private overlay IP address of 10.0.0.3 and a MAC address of M2.Each compute instance in Subnet-1, including compute instances C1 andC2, has a default route to VCN VR 105 using IP address 10.0.0.1, whichis the IP address for a port of VCN VR 105 for Subnet-1.

Subnet-2 can have multiple compute instances deployed on it, includingvirtual machine instances and/or bare metal instances. For example, asshown in FIG. 1 , compute instances D1 and D2 are part of Subnet-2 viaVNICs associated with the respective compute instances. In theembodiment depicted in FIG. 1 , compute instance D1 has an overlay IPaddress of 10.1.0.2 and a MAC address of MM1, while compute instance D2has a private overlay IP address of 10.1.0.3 and a MAC address of MM2.Each compute instance in Subnet-2, including compute instances D1 andD2, has a default route to VCN VR 105 using IP address 10.1.0.1, whichis the IP address for a port of VCN VR 105 for Subnet-2.

VCN A 104 may also include one or more load balancers. For example, aload balancer may be provided for a subnet and may be configured to loadbalance traffic across multiple compute instances on the subnet. A loadbalancer may also be provided to load balance traffic across subnets inthe VCN.

A particular compute instance deployed on VCN 104 can communicate withvarious different endpoints. These endpoints may include endpoints thatare hosted by CSPI 200 and endpoints outside CSPI 200. Endpoints thatare hosted by CSPI 101 may include: an endpoint on the same subnet asthe particular compute instance (e.g., communications between twocompute instances in Subnet-1); an endpoint on a different subnet butwithin the same VCN (e.g., communication between a compute instance inSubnet-1 and a compute instance in Subnet-2); an endpoint in a differentVCN in the same region (e.g., communications between a compute instancein Subnet-1 and an endpoint in a VCN in the same region 106 or 110,communications between a compute instance in Subnet-1 and an endpoint inservice network 110 in the same region); or an endpoint in a VCN in adifferent region (e.g., communications between a compute instance inSubnet-1 and an endpoint in a VCN in a different region 108). A computeinstance in a subnet hosted by CSPI 101 may also communicate withendpoints that are not hosted by CSPI 101 (i.e., are outside CSPI 101).These outside endpoints include endpoints in the customer's on-premisenetwork 116, endpoints within other remote cloud hosted networks 118,public endpoints 114 accessible via a public network such as theInternet, and other endpoints.

Communications between compute instances on the same subnet arefacilitated using VNICs associated with the source compute instance andthe destination compute instance. For example, compute instance C1 inSubnet-1 may want to send packets to compute instance C2 in Subnet-1.For a packet originating at a source compute instance and whosedestination is another compute instance in the same subnet, the packetis first processed by the VNIC associated with the source computeinstance. Processing performed by the VNIC associated with the sourcecompute instance can include determining destination information for thepacket from the packet headers, identifying any policies (e.g., securitylists) configured for the VNIC associated with the source computeinstance, determining a next hop for the packet, performing any packetencapsulation/decapsulation functions as needed, and thenforwarding/routing the packet to the next hop with the goal offacilitating communication of the packet to its intended destination.When the destination compute instance is in the same subnet as thesource compute instance, the VNIC associated with the source computeinstance is configured to identify the VNIC associated with thedestination compute instance and forward the packet to that VNIC forprocessing. The VNIC associated with the destination compute instance isthen executed and forwards the packet to the destination computeinstance.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the communication isfacilitated by the VNICs associated with the source and destinationcompute instances and the VCN VR. For example, if compute instance C1 inSubnet-1 in FIG. 1 wants to send a packet to compute instance D1 inSubnet-2, the packet is first processed by the VNIC associated withcompute instance C1. The VNIC associated with compute instance C1 isconfigured to route the packet to the VCN VR 105 using default route orport 10.0.0.1 of the VCN VR. VCN VR 105 is configured to route thepacket to Subnet-2 using port 10.1.0.1. The packet is then received andprocessed by the VNIC associated with D1 and the VNIC forwards thepacket to compute instance D1.

For a packet to be communicated from a compute instance in VCN 104 to anendpoint that is outside VCN 104, the communication is facilitated bythe VNIC associated with the source compute instance, VCN VR 105, andgateways associated with VCN 104. One or more types of gateways may beassociated with VCN 104. A gateway is an interface between a VCN andanother endpoint, where the another endpoint is outside the VCN. Agateway is a Layer-3/IP layer concept and enables a VCN to communicatewith endpoints outside the VCN. A gateway thus facilitates traffic flowbetween a VCN and other VCNs or networks. Various different types ofgateways may be configured for a VCN to facilitate different types ofcommunications with different types of endpoints. Depending upon thegateway, the communications may be over public networks (e.g., theInternet) or over private networks. Various communication protocols maybe used for these communications.

For example, compute instance C1 may want to communicate with anendpoint outside VCN 104. The packet may be first processed by the VNICassociated with source compute instance C1. The VNIC processingdetermines that the destination for the packet is outside the Subnet-1of C1. The VNIC associated with C1 may forward the packet to VCN VR 105for VCN 104. VCN VR 105 then processes the packet and as part of theprocessing, based upon the destination for the packet, determines aparticular gateway associated with VCN 104 as the next hop for thepacket. VCN VR 105 may then forward the packet to the particularidentified gateway. For example, if the destination is an endpointwithin the customer's on-premise network, then the packet may beforwarded by VCN VR 105 to Dynamic Routing Gateway (DRG) gateway 122configured for VCN 104. The packet may then be forwarded from thegateway to a next hop to facilitate communication of the packet to itfinal intended destination.

Various different types of gateways may be configured for a VCN.Examples of gateways that may be configured for a VCN are depicted inFIG. 1 and described below. Examples of gateways associated with a VCNare also depicted in FIGS. 16, 17, 18, and 19 (for example, gatewaysreferenced by reference numbers 1634, 1636, 1638, 1734, 1736, 1738,1834, 1836, 1838, 1934, 1936, and 1938) and described below. As shown inthe embodiment depicted in FIG. 1 , a Dynamic Routing Gateway (DRG) 122may be added to or be associated with customer VCN 104 and provides apath for private network traffic communication between customer VCN 104and another endpoint, where the another endpoint can be the customer'son-premise network 116, a VCN 108 in a different region of CSPI 101, orother remote cloud networks 118 not hosted by CSPI 101. Customeron-premise network 116 may be a customer network or a customer datacenter built using the customer's resources. Access to customeron-premise network 116 is generally very restricted. For a customer thathas both a customer on-premise network 116 and one or more VCNs 104deployed or hosted in the cloud by CSPI 101, the customer may want theiron-premise network 116 and their cloud-based VCN 104 to be able tocommunicate with each other. This enables a customer to build anextended hybrid environment encompassing the customer's VCN 104 hostedby CSPI 101 and their on-premises network 116. DRG 122 enables thiscommunication. To enable such communications, a communication channel124 is set up where one endpoint of the channel is in customeron-premise network 116 and the other endpoint is in CSPI 101 andconnected to customer VCN 104. Communication channel 124 can be overpublic communication networks such as the Internet or privatecommunication networks. Various different communication protocols may beused such as IPsec VPN technology over a public communication networksuch as the Internet, Oracle's FastConnect technology that uses aprivate network instead of a public network, and others. The device orequipment in customer on-premise network 116 that forms one end pointfor communication channel 124 is referred to as the customer premiseequipment (CPE), such as CPE 126 depicted in FIG. 1 . On the CSPI 101side, the endpoint may be a host machine executing DRG 122.

In certain embodiments, a Remote Peering Connection (RPC) can be addedto a DRG, which allows a customer to peer one VCN with another VCN in adifferent region. Using such an RPC, customer VCN 104 can use DRG 122 toconnect with a VCN 108 in another region. DRG 122 may also be used tocommunicate with other remote cloud networks 118, not hosted by CSPI 101such as a Microsoft Azure cloud, Amazon AWS cloud, and others.

As shown in FIG. 1 , an Internet Gateway (IGW) 120 may be configured forcustomer VCN 104 the enables a compute instance on VCN 104 tocommunicate with public endpoints 114 accessible over a public networksuch as the Internet. IGW 1120 is a gateway that connects a VCN to apublic network such as the Internet. IGW 120 enables a public subnet(where the resources in the public subnet have public overlay IPaddresses) within a VCN, such as VCN 104, direct access to publicendpoints 112 on a public network 114 such as the Internet. Using IGW120, connections can be initiated from a subnet within VCN 104 or fromthe Internet.

A Network Address Translation (NAT) gateway 128 can be configured forcustomer's VCN 104 and enables cloud resources in the customer's VCN,which do not have dedicated public overlay IP addresses, access to theInternet and it does so without exposing those resources to directincoming Internet connections (e.g., L4-L7 connections). This enables aprivate subnet within a VCN, such as private Subnet-1 in VCN 104, withprivate access to public endpoints on the Internet. In NAT gateways,connections can be initiated only from the private subnet to the publicInternet and not from the Internet to the private subnet.

In certain embodiments, a Service Gateway (SGW) 126 can be configuredfor customer VCN 104 and provides a path for private network trafficbetween VCN 104 and supported services endpoints in a service network110. In certain embodiments, service network 110 may be provided by theCSP and may provide various services. An example of such a servicenetwork is Oracle's Services Network, which provides various servicesthat can be used by customers. For example, a compute instance (e.g., adatabase system) in a private subnet of customer VCN 104 can back updata to a service endpoint (e.g., Object Storage) without needing publicIP addresses or access to the Internet. In certain embodiments, a VCNcan have only one SGW, and connections can only be initiated from asubnet within the VCN and not from service network 110. If a VCN ispeered with another, resources in the other VCN typically cannot accessthe SGW. Resources in on-premises networks that are connected to a VCNwith FastConnect or VPN Connect can also use the service gatewayconfigured for that VCN.

In certain implementations, SGW 126 uses the concept of a serviceClassless Inter-Domain Routing (CIDR) label, which is a string thatrepresents all the regional public IP address ranges for the service orgroup of services of interest. The customer uses the service CIDR labelwhen they configure the SGW and related route rules to control trafficto the service. The customer can optionally utilize it when configuringsecurity rules without needing to adjust them if the service's public IPaddresses change in the future.

A Local Peering Gateway (LPG) 132 is a gateway that can be added tocustomer VCN 104 and enables VCN 104 to peer with another VCN in thesame region. Peering means that the VCNs communicate using private IPaddresses, without the traffic traversing a public network such as theInternet or without routing the traffic through the customer'son-premises network 116. In preferred embodiments, a VCN has a separateLPG for each peering it establishes. Local Peering or VCN Peering is acommon practice used to establish network connectivity between differentapplications or infrastructure management functions.

Service providers, such as providers of services in service network 110,may provide access to services using different access models. Accordingto a public access model, services may be exposed as public endpointsthat are publicly accessible by compute instance in a customer VCN via apublic network such as the Internet and or may be privately accessiblevia SGW 126. According to a specific private access model, services aremade accessible as private IP endpoints in a private subnet in thecustomer's VCN. This is referred to as a Private Endpoint (PE) accessand enables a service provider to expose their service as an instance inthe customer's private network. A Private Endpoint resource represents aservice within the customer's VCN. Each PE manifests as a VNIC (referredto as a PE-VNIC, with one or more private IPs) in a subnet chosen by thecustomer in the customer's VCN. A PE thus provides a way to present aservice within a private customer VCN subnet using a VNIC. Since theendpoint is exposed as a VNIC, all the features associates with a VNICsuch as routing rules, security lists, etc., are now available for thePE VNIC.

A service provider can register their service to enable access through aPE. The provider can associate policies with the service that restrictsthe service's visibility to the customer tenancies. A provider canregister multiple services under a single virtual IP address (VIP),especially for multi-tenant services. There may be multiple such privateendpoints (in multiple VCNs) that represent the same service.

Compute instances in the private subnet can then use the PE VNIC'sprivate IP address or the service DNS name to access the service.Compute instances in the customer VCN can access the service by sendingtraffic to the private IP address of the PE in the customer VCN. APrivate Access Gateway (PAGW) 130 is a gateway resource that can beattached to a service provider VCN (e.g., a VCN in service network 110)that acts as an ingress/egress point for all traffic from/to customersubnet private endpoints. PAGW 130 enables a provider to scale thenumber of PE connections without utilizing its internal IP addressresources. A provider needs only configure one PAGW for any number ofservices registered in a single VCN. Providers can represent a serviceas a private endpoint in multiple VCNs of one or more customers. Fromthe customer's perspective, the PE VNIC, which, instead of beingattached to a customer's instance, appears attached to the service withwhich the customer wishes to interact. The traffic destined to theprivate endpoint is routed via PAGW 130 to the service. These arereferred to as customer-to-service private connections (C2Sconnections).

The PE concept can also be used to extend the private access for theservice to customer's on-premises networks and data centers, by allowingthe traffic to flow through FastConnect/IPsec links and the privateendpoint in the customer VCN. Private access for the service can also beextended to the customer's peered VCNs, by allowing the traffic to flowbetween LPG 132 and the PE in the customer's VCN.

A customer can control routing in a VCN at the subnet level, so thecustomer can specify which subnets in the customer's VCN, such as VCN104, use each gateway. A VCN's route tables are used to decide iftraffic is allowed out of a VCN through a particular gateway. Forexample, in a particular instance, a route table for a public subnetwithin customer VCN 104 may send non-local traffic through IGW 120. Theroute table for a private subnet within the same customer VCN 104 maysend traffic destined for CSP services through SGW 126. All remainingtraffic may be sent via the NAT gateway 128. Route tables only controltraffic going out of a VCN.

Security lists associated with a VCN are used to control traffic thatcomes into a VCN via a gateway via inbound connections. All resources ina subnet use the same route table and security lists. Security lists maybe used to control specific types of traffic allowed in and out ofinstances in a subnet of a VCN. Security list rules may comprise ingress(inbound) and egress (outbound) rules. For example, an ingress rule mayspecify an allowed source address range, while an egress rule mayspecify an allowed destination address range. Security rules may specifya particular protocol (e.g., TCP, ICMP), a particular port (e.g., 22 forSSH, 3389 for Windows RDP), etc. In certain implementations, aninstance's operating system may enforce its own firewall rules that arealigned with the security list rules. Rules may be stateful (e.g., aconnection is tracked and the response is automatically allowed withoutan explicit security list rule for the response traffic) or stateless.

Access from a customer VCN (i.e., by a resource or compute instancedeployed on VCN 104) can be categorized as public access, privateaccess, or dedicated access. Public access refers to an access modelwhere a public IP address or a NAT is used to access a public endpoint.Private access enables customer workloads in VCN 104 with private IPaddresses (e.g., resources in a private subnet) to access serviceswithout traversing a public network such as the Internet. In certainembodiments, CSPI 101 enables customer VCN workloads with private IPaddresses to access the (public service endpoints of) services using aservice gateway. A service gateway thus offers a private access model byestablishing a virtual link between the customer's VCN and the service'spublic endpoint residing outside the customer's private network.

Additionally, CSPI may offer dedicated public access using technologiessuch as FastConnect public peering where customer on-premises instancescan access one or more services in a customer VCN using a FastConnectconnection and without traversing a public network such as the Internet.CSPI also may also offer dedicated private access using FastConnectprivate peering where customer on-premises instances with private IPaddresses can access the customer's VCN workloads using a FastConnectconnection. FastConnect is a network connectivity alternative to usingthe public Internet to connect a customer's on-premise network to CSPIand its services. FastConnect provides an easy, elastic, and economicalway to create a dedicated and private connection with higher bandwidthoptions and a more reliable and consistent networking experience whencompared to Internet-based connections.

FIG. 1 and the accompanying description above describes variousvirtualized components in an example virtual network. As describedabove, the virtual network is built on the underlying physical orsubstrate network. FIG. 2 depicts a simplified architectural diagram ofthe physical components in the physical network within CSPI 200 thatprovide the underlay for the virtual network according to certainembodiments. As shown, CSPI 200 provides a distributed environmentcomprising components and resources (e.g., compute, memory, andnetworking resources) provided by a cloud service provider (CSP). Thesecomponents and resources are used to provide cloud services (e.g., IaaSservices) to subscribing customers, i.e., customers that have subscribedto one or more services provided by the CSP. Based upon the servicessubscribed to by a customer, a subset of resources (e.g., compute,memory, and networking resources) of CSPI 200 are provisioned for thecustomer. Customers can then build their own cloud-based (i.e.,CSPI-hosted) customizable and private virtual networks using physicalcompute, memory, and networking resources provided by CSPI 200. Aspreviously indicated, these customer networks are referred to as virtualcloud networks (VCNs). A customer can deploy one or more customerresources, such as compute instances, on these customer VCNs. Computeinstances can be in the form of virtual machines, bare metal instances,and the like. CSPI 200 provides infrastructure and a set ofcomplementary cloud services that enable customers to build and run awide range of applications and services in a highly available hostedenvironment.

In the example embodiment depicted in FIG. 2 , the physical componentsof CSPI 200 include one or more physical host machines or physicalservers (e.g., 202, 206, 208), network virtualization devices (NVDs)(e.g., 210, 212), top-of-rack (TOR) switches (e.g., 214, 216), and aphysical network (e.g., 218), and switches in physical network 218. Thephysical host machines or servers may host and execute various computeinstances that participate in one or more subnets of a VCN. The computeinstances may include virtual machine instances, and bare metalinstances. For example, the various compute instances depicted in FIG. 1may be hosted by the physical host machines depicted in FIG. 2 . Thevirtual machine compute instances in a VCN may be executed by one hostmachine or by multiple different host machines. The physical hostmachines may also host virtual host machines, container-based hosts orfunctions, and the like. The VNICs and VCN VR depicted in FIG. 1 may beexecuted by the NVDs depicted in FIG. 2 . The gateways depicted in FIG.1 may be executed by the host machines and/or by the NVDs depicted inFIG. 2 .

The host machines or servers may execute a hypervisor (also referred toas a virtual machine monitor or VMM) that creates and enables avirtualized environment on the host machines. The virtualization orvirtualized environment facilitates cloud-based computing. One or morecompute instances may be created, executed, and managed on a hostmachine by a hypervisor on that host machine. The hypervisor on a hostmachine enables the physical computing resources of the host machine(e.g., compute, memory, and networking resources) to be shared betweenthe various compute instances executed by the host machine.

For example, as depicted in FIG. 2 , host machines 202 and 208 executehypervisors 260 and 266, respectively. These hypervisors may beimplemented using software, firmware, or hardware, or combinationsthereof. Typically, a hypervisor is a process or a software layer thatsits on top of the host machine's operating system (OS), which in turnexecutes on the hardware processors of the host machine. The hypervisorprovides a virtualized environment by enabling the physical computingresources (e.g., processing resources such as processors/cores, memoryresources, networking resources) of the host machine to be shared amongthe various virtual machine compute instances executed by the hostmachine. For example, in FIG. 2 , hypervisor 260 may sit on top of theOS of host machine 202 and enables the computing resources (e.g.,processing, memory, and networking resources) of host machine 202 to beshared between compute instances (e.g., virtual machines) executed byhost machine 202. A virtual machine can have its own operating system(referred to as a guest operating system), which may be the same as ordifferent from the OS of the host machine. The operating system of avirtual machine executed by a host machine may be the same as ordifferent from the operating system of another virtual machine executedby the same host machine. A hypervisor thus enables multiple operatingsystems to be executed alongside each other while sharing the samecomputing resources of the host machine. The host machines depicted inFIG. 2 may have the same or different types of hypervisors.

A compute instance can be a virtual machine instance or a bare metalinstance. In FIG. 2 , compute instances 268 on host machine 202 and 274on host machine 208 are examples of virtual machine instances. Hostmachine 206 is an example of a bare metal instance that is provided to acustomer.

In certain instances, an entire host machine may be provisioned to asingle customer, and all of the one or more compute instances (eithervirtual machines or bare metal instance) hosted by that host machinebelong to that same customer. In other instances, a host machine may beshared between multiple customers (i.e., multiple tenants). In such amulti-tenancy scenario, a host machine may host virtual machine computeinstances belonging to different customers. These compute instances maybe members of different VCNs of different customers. In certainembodiments, a bare metal compute instance is hosted by a bare metalserver without a hypervisor. When a bare metal compute instance isprovisioned, a single customer or tenant maintains control of thephysical CPU, memory, and network interfaces of the host machine hostingthe bare metal instance and the host machine is not shared with othercustomers or tenants.

As previously described, each compute instance that is part of a VCN isassociated with a VNIC that enables the compute instance to become amember of a subnet of the VCN. The VNIC associated with a computeinstance facilitates the communication of packets or frames to and fromthe compute instance. A VNIC is associated with a compute instance whenthe compute instance is created. In certain embodiments, for a computeinstance executed by a host machine, the VNIC associated with thatcompute instance is executed by an NVD connected to the host machine.For example, in FIG. 2 , host machine 202 executes a virtual machinecompute instance 268 that is associated with VNIC 276, and VNIC 276 isexecuted by NVD 210 connected to host machine 202. As another example,bare metal instance 272 hosted by host machine 206 is associated withVNIC 280 that is executed by NVD 212 connected to host machine 206. Asyet another example, VNIC 284 is associated with compute instance 274executed by host machine 208, and VNIC 284 is executed by NVD 212connected to host machine 208.

For compute instances hosted by a host machine, an NVD connected to thathost machine also executes VCN VRs corresponding to VCNs of which thecompute instances are members. For example, in the embodiment depictedin FIG. 2 , NVD 210 executes VCN VR 277 corresponding to the VCN ofwhich compute instance 268 is a member. NVD 212 may also execute one ormore VCN VRs 283 corresponding to VCNs corresponding to the computeinstances hosted by host machines 206 and 208.

A host machine may include one or more network interface cards (NIC)that enable the host machine to be connected to other devices. A NIC ona host machine may provide one or more ports (or interfaces) that enablethe host machine to be communicatively connected to another device. Forexample, a host machine may be connected to an NVD using one or moreports (or interfaces) provided on the host machine and on the NVD. Ahost machine may also be connected to other devices such as another hostmachine.

For example, in FIG. 2 , host machine 202 is connected to NVD 210 usinglink 220 that extends between a port 234 provided by a NIC 232 of hostmachine 202 and between a port 236 of NVD 210. Host machine 206 isconnected to NVD 212 using link 224 that extends between a port 246provided by a NIC 244 of host machine 206 and between a port 248 of NVD212. Host machine 208 is connected to NVD 212 using link 226 thatextends between a port 252 provided by a NIC 250 of host machine 208 andbetween a port 254 of NVD 212.

The NVDs are in turn connected via communication links totop-of-the-rack (TOR) switches, which are connected to physical network218 (also referred to as the switch fabric). In certain embodiments, thelinks between a host machine and an NVD, and between an NVD and a TORswitch are Ethernet links. For example, in FIG. 2 , NVDs 210 and 212 areconnected to TOR switches 214 and 216, respectively, using links 228 and230. In certain embodiments, the links 220, 224, 226, 228, and 230 areEthernet links. The collection of host machines and NVDs that areconnected to a TOR is sometimes referred to as a rack.

Physical network 218 provides a communication fabric that enables TORswitches to communicate with each other. Physical network 218 can be amulti-tiered network. In certain implementations, physical network 218is a multi-tiered Clos network of switches, with TOR switches 214 and216 representing the leaf level nodes of the multi-tiered and multi-nodephysical switching network 218. Different Clos network configurationsare possible including but not limited to a 2-tier network, a 3-tiernetwork, a 4-tier network, a 5-tier network, and in general a “n”-tierednetwork. An example of a Clos network is depicted in FIG. 5 anddescribed below.

Various different connection configurations are possible between hostmachines and NVDs such as one-to-one configuration, many-to-oneconfiguration, one-to-many configuration, and others. In a one-to-oneconfiguration implementation, each host machine is connected to its ownseparate NVD. For example, in FIG. 2 , host machine 202 is connected toNVD 210 via NIC 232 of host machine 202. In a many-to-one configuration,multiple host machines are connected to one NVD. For example, in FIG. 2, host machines 206 and 208 are connected to the same NVD 212 via NICs244 and 250, respectively.

In a one-to-many configuration, one host machine is connected tomultiple NVDs. FIG. 3 shows an example within CSPI 300 where a hostmachine is connected to multiple NVDs. As shown in FIG. 3 , host machine302 comprises a network interface card (NIC) 304 that includes multipleports 306 and 308. Host machine 300 is connected to a first NVD 310 viaport 306 and link 320, and connected to a second NVD 312 via port 308and link 322. Ports 306 and 308 may be Ethernet ports and the links 320and 322 between host machine 302 and NVDs 310 and 312 may be Ethernetlinks. NVD 310 is in turn connected to a first TOR switch 314 and NVD312 is connected to a second TOR switch 316. The links between NVDs 310and 312, and TOR switches 314 and 316 may be Ethernet links. TORswitches 314 and 316 represent the Tier-0 switching devices inmulti-tiered physical network 318.

The arrangement depicted in FIG. 3 provides two separate physicalnetwork paths to and from physical switch network 318 to host machine302: a first path traversing TOR switch 314 to NVD 310 to host machine302, and a second path traversing TOR switch 316 to NVD 312 to hostmachine 302. The separate paths provide for enhanced availability(referred to as high availability) of host machine 302. If there areproblems in one of the paths (e.g., a link in one of the paths goesdown) or devices (e.g., a particular NVD is not functioning), then theother path may be used for communications to/from host machine 302.

In the configuration depicted in FIG. 3 , the host machine is connectedto two different NVDs using two different ports provided by a NIC of thehost machine. In other embodiments, a host machine may include multipleNICs that enable connectivity of the host machine to multiple NVDs.

Referring back to FIG. 2 , an NVD is a physical device or component thatperforms one or more network and/or storage virtualization functions. AnNVD may be any device with one or more processing units (e.g., CPUs,Network Processing Units (NPUs), FPGAs, packet processing pipelines,etc.), memory including cache, and ports. The various virtualizationfunctions may be performed by software/firmware executed by the one ormore processing units of the NVD.

An NVD may be implemented in various different forms. For example, incertain embodiments, an NVD is implemented as an interface card referredto as a smartNIC or an intelligent NIC with an embedded processoronboard. A smartNIC is a separate device from the NICs on the hostmachines. In FIG. 2 , the NVDs 210 and 212 may be implemented assmartNICs that are connected to host machines 202, and host machines 206and 208, respectively.

A smartNIC is however just one example of an NVD implementation. Variousother implementations are possible. For example, in some otherimplementations, an NVD or one or more functions performed by the NVDmay be incorporated into or performed by one or more host machines, oneor more TOR switches, and other components of CSPI 200. For example, anNVD may be embodied in a host machine where the functions performed byan NVD are performed by the host machine. As another example, an NVD maybe part of a TOR switch or a TOR switch may be configured to performfunctions performed by an NVD that enables the TOR switch to performvarious complex packet transformations that are used for a public cloud.A TOR that performs the functions of an NVD is sometimes referred to asa smart TOR. In yet other implementations, where virtual machines (VMs)instances, but not bare metal (BM) instances, are offered to customers,functions performed by an NVD may be implemented inside a hypervisor ofthe host machine. In some other implementations, some of the functionsof the NVD may be offloaded to a centralized service running on a fleetof host machines.

In certain embodiments, such as when implemented as a smartNIC as shownin FIG. 2 , an NVD may comprise multiple physical ports that enable itto be connected to one or more host machines and to one or more TORswitches. A port on an NVD can be classified as a host-facing port (alsoreferred to as a “south port”) or a network-facing or TOR-facing port(also referred to as a “north port”). A host-facing port of an NVD is aport that is used to connect the NVD to a host machine. Examples ofhost-facing ports in FIG. 2 include port 236 on NVD 210, and ports 248and 254 on NVD 212. A network-facing port of an NVD is a port that isused to connect the NVD to a TOR switch. Examples of network-facingports in FIG. 2 include port 256 on NVD 210, and port 258 on NVD 212. Asshown in FIG. 2 , NVD 210 is connected to TOR switch 214 using link 228that extends from port 256 of NVD 210 to the TOR switch 214. Likewise,NVD 212 is connected to TOR switch 216 using link 230 that extends fromport 258 of NVD 212 to the TOR switch 216.

An NVD receives packets and frames from a host machine (e.g., packetsand frames generated by a compute instance hosted by the host machine)via a host-facing port and, after performing the necessary packetprocessing, may forward the packets and frames to a TOR switch via anetwork-facing port of the NVD. An NVD may receive packets and framesfrom a TOR switch via a network-facing port of the NVD and, afterperforming the necessary packet processing, may forward the packets andframes to a host machine via a host-facing port of the NVD.

In certain embodiments, there may be multiple ports and associated linksbetween an NVD and a TOR switch. These ports and links may be aggregatedto form a link aggregator group of multiple ports or links (referred toas a LAG). Link aggregation allows multiple physical links between twoend-points (e.g., between an NVD and a TOR switch) to be treated as asingle logical link. All the physical links in a given LAG may operatein full-duplex mode at the same speed. LAGs help increase the bandwidthand reliability of the connection between two endpoints. If one of thephysical links in the LAG goes down, traffic is dynamically andtransparently reassigned to one of the other physical links in the LAG.The aggregated physical links deliver higher bandwidth than eachindividual link. The multiple ports associated with a LAG are treated asa single logical port. Traffic can be load-balanced across the multiplephysical links of a LAG. One or more LAGs may be configured between twoendpoints. The two endpoints may be between an NVD and a TOR switch,between a host machine and an NVD, and the like.

An NVD implements or performs network virtualization functions. Thesefunctions are performed by software/firmware executed by the NVD.Examples of network virtualization functions include without limitation:packet encapsulation and de-capsulation functions; functions forcreating a VCN network; functions for implementing network policies suchas VCN security list (firewall) functionality; functions that facilitatethe routing and forwarding of packets to and from compute instances in aVCN; and the like. In certain embodiments, upon receiving a packet, anNVD is configured to execute a packet processing pipeline for processingthe packet and determining how the packet is to be forwarded or routed.As part of this packet processing pipeline, the NVD may execute one ormore virtual functions associated with the overlay network such asexecuting VNICs associated with compute instances in the VCN, executinga Virtual Router (VR) associated with the VCN, the encapsulation anddecapsulation of packets to facilitate forwarding or routing in thevirtual network, execution of certain gateways (e.g., the Local PeeringGateway), the implementation of Security Lists, Network Security Groups,network address translation (NAT) functionality (e.g., the translationof Public IP to Private IP on a host by host basis), throttlingfunctions, and other functions.

In certain embodiments, the packet processing data path in an NVD maycomprise multiple packet pipelines, each composed of a series of packettransformation stages. In certain implementations, upon receiving apacket, the packet is parsed and classified to a single pipeline. Thepacket is then processed in a linear fashion, one stage after another,until the packet is either dropped or sent out over an interface of theNVD. These stages provide basic functional packet processing buildingblocks (e.g., validating headers, enforcing throttle, inserting newLayer-2 headers, enforcing L4 firewall, VCN encapsulation/decapsulation,etc.) so that new pipelines can be constructed by composing existingstages, and new functionality can be added by creating new stages andinserting them into existing pipelines.

An NVD may perform both control plane and data plane functionscorresponding to a control plane and a data plane of a VCN. Examples ofa VCN Control Plane are also depicted in FIGS. 16, 17, 18, and 19 (seereferences 1616, 1716, 1816, and 1916) and described below. Examples ofa VCN Data Plane are depicted in FIGS. 16, 17, 18, and 19 (seereferences 1618, 1718, 1818, and 1918) and described below. The controlplane functions include functions used for configuring a network (e.g.,setting up routes and route tables, configuring VNICs, etc.) thatcontrols how data is to be forwarded. In certain embodiments, a VCNControl Plane is provided that computes all the overlay-to-substratemappings centrally and publishes them to the NVDs and to the virtualnetwork edge devices such as various gateways such as the DRG, the SGW,the IGW, etc. Firewall rules may also be published using the samemechanism. In certain embodiments, an NVD only gets the mappings thatare relevant for that NVD. The data plane functions include functionsfor the actual routing/forwarding of a packet based upon configurationset up using control plane. A VCN data plane is implemented byencapsulating the customer's network packets before they traverse thesubstrate network. The encapsulation/decapsulation functionality isimplemented on the NVDs. In certain embodiments, an NVD is configured tointercept all network packets in and out of host machines and performnetwork virtualization functions.

As indicated above, an NVD executes various virtualization functionsincluding VNICs and VCN VRs. An NVD may execute VNICs associated withthe compute instances hosted by one or more host machines connected tothe VNIC. For example, as depicted in FIG. 2 , NVD 210 executes thefunctionality for VNIC 276 that is associated with compute instance 268hosted by host machine 202 connected to NVD 210. As another example, NVD212 executes VNIC 280 that is associated with bare metal computeinstance 272 hosted by host machine 206, and executes VNIC 284 that isassociated with compute instance 274 hosted by host machine 208. A hostmachine may host compute instances belonging to different VCNs, whichbelong to different customers, and the NVD connected to the host machinemay execute the VNICs (i.e., execute VNICs-relate functionality)corresponding to the compute instances.

An NVD also executes VCN Virtual Routers corresponding to the VCNs ofthe compute instances. For example, in the embodiment depicted in FIG. 2, NVD 210 executes VCN VR 277 corresponding to the VCN to which computeinstance 268 belongs. NVD 212 executes one or more VCN VRs 283corresponding to one or more VCNs to which compute instances hosted byhost machines 206 and 208 belong. In certain embodiments, the VCN VRcorresponding to that VCN is executed by all the NVDs connected to hostmachines that host at least one compute instance belonging to that VCN.If a host machine hosts compute instances belonging to different VCNs,an NVD connected to that host machine may execute VCN VRs correspondingto those different VCNs.

In addition to VNICs and VCN VRs, an NVD may execute various software(e.g., daemons) and include one or more hardware components thatfacilitate the various network virtualization functions performed by theNVD. For purposes of simplicity, these various components are groupedtogether as “packet processing components” shown in FIG. 2 . Forexample, NVD 210 comprises packet processing components 286 and NVD 212comprises packet processing components 288. For example, the packetprocessing components for an NVD may include a packet processor that isconfigured to interact with the NVD's ports and hardware interfaces tomonitor all packets received by and communicated using the NVD and storenetwork information. The network information may, for example, includenetwork flow information identifying different network flows handled bythe NVD and per flow information (e.g., per flow statistics). In certainembodiments, network flows information may be stored on a per VNICbasis. The packet processor may perform packet-by-packet manipulationsas well as implement stateful NAT and L4 firewall (FW). As anotherexample, the packet processing components may include a replicationagent that is configured to replicate information stored by the NVD toone or more different replication target stores. As yet another example,the packet processing components may include a logging agent that isconfigured to perform logging functions for the NVD. The packetprocessing components may also include software for monitoring theperformance and health of the NVD and, also possibly of monitoring thestate and health of other components connected to the NVD.

FIG. 1 shows the components of an example virtual or overlay networkincluding a VCN, subnets within the VCN, compute instances deployed onsubnets, VNICs associated with the compute instances, a VR for a VCN,and a set of gateways configured for the VCN. The overlay componentsdepicted in FIG. 1 may be executed or hosted by one or more of thephysical components depicted in FIG. 2 . For example, the computeinstances in a VCN may be executed or hosted by one or more hostmachines depicted in FIG. 2 . For a compute instance hosted by a hostmachine, the VNIC associated with that compute instance is typicallyexecuted by an NVD connected to that host machine (i.e., the VNICfunctionality is provided by the NVD connected to that host machine).The VCN VR function for a VCN is executed by all the NVDs that areconnected to host machines hosting or executing the compute instancesthat are part of that VCN. The gateways associated with a VCN may beexecuted by one or more different types of NVDs. For example, certaingateways may be executed by smartNICs, while others may be executed byone or more host machines or other implementations of NVDs.

As described above, a compute instance in a customer VCN may communicatewith various different endpoints, where the endpoints can be within thesame subnet as the source compute instance, in a different subnet butwithin the same VCN as the source compute instance, or with an endpointthat is outside the VCN of the source compute instance. Thesecommunications are facilitated using VNICs associated with the computeinstances, the VCN VRs, and the gateways associated with the VCNs.

For communications between two compute instances on the same subnet in aVCN, the communication is facilitated using VNICs associated with thesource and destination compute instances. The source and destinationcompute instances may be hosted by the same host machine or by differenthost machines. A packet originating from a source compute instance maybe forwarded from a host machine hosting the source compute instance toan NVD connected to that host machine. On the NVD, the packet isprocessed using a packet processing pipeline, which can includeexecution of the VNIC associated with the source compute instance. Sincethe destination endpoint for the packet is within the same subnet,execution of the VNIC associated with the source compute instanceresults in the packet being forwarded to an NVD executing the VNICassociated with the destination compute instance, which then processesand forwards the packet to the destination compute instance. The VNICsassociated with the source and destination compute instances may beexecuted on the same NVD (e.g., when both the source and destinationcompute instances are hosted by the same host machine) or on differentNVDs (e.g., when the source and destination compute instances are hostedby different host machines connected to different NVDs). The VNICs mayuse routing/forwarding tables stored by the NVD to determine the nexthop for the packet.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the packetoriginating from the source compute instance is communicated from thehost machine hosting the source compute instance to the NVD connected tothat host machine. On the NVD, the packet is processed using a packetprocessing pipeline, which can include execution of one or more VNICs,and the VR associated with the VCN. For example, as part of the packetprocessing pipeline, the NVD executes or invokes functionalitycorresponding to the VNIC (also referred to as executes the VNIC)associated with source compute instance. The functionality performed bythe VNIC may include looking at the VLAN tag on the packet. Since thepacket's destination is outside the subnet, the VCN VR functionality isnext invoked and executed by the NVD. The VCN VR then routes the packetto the NVD executing the VNIC associated with the destination computeinstance. The VNIC associated with the destination compute instance thenprocesses the packet and forwards the packet to the destination computeinstance. The VNICs associated with the source and destination computeinstances may be executed on the same NVD (e.g., when both the sourceand destination compute instances are hosted by the same host machine)or on different NVDs (e.g., when the source and destination computeinstances are hosted by different host machines connected to differentNVDs).

If the destination for the packet is outside the VCN of the sourcecompute instance, then the packet originating from the source computeinstance is communicated from the host machine hosting the sourcecompute instance to the NVD connected to that host machine. The NVDexecutes the VNIC associated with the source compute instance. Since thedestination end point of the packet is outside the VCN, the packet isthen processed by the VCN VR for that VCN. The NVD invokes the VCN VRfunctionality, which may result in the packet being forwarded to an NVDexecuting the appropriate gateway associated with the VCN. For example,if the destination is an endpoint within the customer's on-premisenetwork, then the packet may be forwarded by the VCN VR to the NVDexecuting the DRG gateway configured for the VCN. The VCN VR may beexecuted on the same NVD as the NVD executing the VNIC associated withthe source compute instance or by a different NVD. The gateway may beexecuted by an NVD, which may be a smartNIC, a host machine, or otherNVD implementation. The packet is then processed by the gateway andforwarded to a next hop that facilitates communication of the packet toits intended destination endpoint. For example, in the embodimentdepicted in FIG. 2 , a packet originating from compute instance 268 maybe communicated from host machine 202 to NVD 210 over link 220 (usingNIC 232). On NVD 210, VNIC 276 is invoked since it is the VNICassociated with source compute instance 268. VNIC 276 is configured toexamine the encapsulated information in the packet, and determine a nexthop for forwarding the packet with the goal of facilitatingcommunication of the packet to its intended destination endpoint, andthen forward the packet to the determined next hop.

A compute instance deployed on a VCN can communicate with variousdifferent endpoints. These endpoints may include endpoints that arehosted by CSPI 200 and endpoints outside CSPI 200. Endpoints hosted byCSPI 200 may include instances in the same VCN or other VCNs, which maybe the customer's VCNs, or VCNs not belonging to the customer.Communications between endpoints hosted by CSPI 200 may be performedover physical network 218. A compute instance may also communicate withendpoints that are not hosted by CSPI 200, or are outside CSPI 200.Examples of these endpoints include endpoints within a customer'son-premise network or data center, or public endpoints accessible over apublic network such as the Internet. Communications with endpointsoutside CSPI 200 may be performed over public networks (e.g., theInternet) (not shown in FIG. 2 ) or private networks (not shown in FIG.2 ) using various communication protocols.

The architecture of CSPI 200 depicted in FIG. 2 is merely an example andis not intended to be limiting. Variations, alternatives, andmodifications are possible in alternative embodiments. For example, insome implementations, CSPI 200 may have more or fewer systems orcomponents than those shown in FIG. 2 , may combine two or more systems,or may have a different configuration or arrangement of systems. Thesystems, subsystems, and other components depicted in FIG. 2 may beimplemented in software (e.g., code, instructions, program) executed byone or more processing units (e.g., processors, cores) of the respectivesystems, using hardware, or combinations thereof. The software may bestored on a non-transitory storage medium (e.g., on a memory device).

FIG. 4 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments. As depicted in FIG. 4 , host machine 402 executes ahypervisor 404 that provides a virtualized environment. Host machine 402executes two virtual machine instances, VM1 406 belonging tocustomer/tenant #1 and VM2 408 belonging to customer/tenant #2. Hostmachine 402 comprises a physical NIC 410 that is connected to an NVD 412via link 414. Each of the compute instances is attached to a VNIC thatis executed by NVD 412. In the embodiment in FIG. 4 , VM1 406 isattached to VNIC-VM1 420 and VM2 408 is attached to VNIC-VM2 422.

As shown in FIG. 4 , NIC 410 comprises two logical NICs, logical NIC A416 and logical NIC B 418. Each virtual machine is attached to andconfigured to work with its own logical NIC. For example, VM1 406 isattached to logical NIC A 416 and VM2 408 is attached to logical NIC B418. Even though host machine 402 comprises only one physical NIC 410that is shared by the multiple tenants, due to the logical NICs, eachtenant's virtual machine believes they have their own host machine andNIC.

In certain embodiments, each logical NIC is assigned its own VLAN ID.Thus, a specific VLAN ID is assigned to logical NIC A 416 for Tenant #1and a separate VLAN ID is assigned to logical NIC B 418 for Tenant #2.When a packet is communicated from VM1 406, a tag assigned to Tenant #1is attached to the packet by the hypervisor and the packet is thencommunicated from host machine 402 to NVD 412 over link 414. In asimilar manner, when a packet is communicated from VM2 408, a tagassigned to Tenant #2 is attached to the packet by the hypervisor andthe packet is then communicated from host machine 402 to NVD 412 overlink 414. Accordingly, a packet 424 communicated from host machine 402to NVD 412 has an associated tag 426 that identifies a specific tenantand associated VM. On the NVD, for a packet 424 received from hostmachine 402, the tag 426 associated with the packet is used to determinewhether the packet is to be processed by VNIC-VM1 420 or by VNIC-VM2422. The packet is then processed by the corresponding VNIC. Theconfiguration depicted in FIG. 4 enables each tenant's compute instanceto believe that they own their own host machine and NIC. The setupdepicted in FIG. 4 provides for I/O virtualization for supportingmulti-tenancy.

FIG. 5 depicts a simplified block diagram of a physical network 500according to certain embodiments. The embodiment depicted in FIG. 5 isstructured as a Clos network. A Clos network is a particular type ofnetwork topology designed to provide connection redundancy whilemaintaining high bisection bandwidth and maximum resource utilization. AClos network is a type of non-blocking, multistage or multi-tieredswitching network, where the number of stages or tiers can be two,three, four, five, etc. The embodiment depicted in FIG. 5 is a 3-tierednetwork comprising tiers 1, 2, and 3. The TOR switches 504 representTier-0 switches in the Clos network. One or more NVDs are connected tothe TOR switches. Tier-0 switches are also referred to as edge devicesof the physical network. The Tier-0 switches are connected to Tier-1switches, which are also referred to as leaf switches. In the embodimentdepicted in FIG. 5 , a set of “n” Tier-0 TOR switches are connected to aset of “n” Tier-1 switches and together form a pod. Each Tier-0 switchin a pod is interconnected to all the Tier-1 switches in the pod, butthere is no connectivity of switches between pods. In certainimplementations, two pods are referred to as a block. Each block isserved by or connected to a set of “n” Tier-2 switches (sometimesreferred to as spine switches). There can be several blocks in thephysical network topology. The Tier-2 switches are in turn connected to“n” Tier-3 switches (sometimes referred to as super-spine switches).Communication of packets over physical network 500 is typicallyperformed using one or more Layer-3 communication protocols. Typically,all the layers of the physical network, except for the TORs layer aren-ways redundant thus allowing for high availability. Policies may bespecified for pods and blocks to control the visibility of switches toeach other in the physical network so as to enable scaling of thephysical network.

A feature of a Clos network is that the maximum hop count to reach fromone Tier-0 switch to another Tier-0 switch (or from an NVD connected toa Tier-0-switch to another NVD connected to a Tier-0 switch) is fixed.For example, in a 3-Tiered Clos network at most seven hops are neededfor a packet to reach from one NVD to another NVD, where the source andtarget NVDs are connected to the leaf tier of the Clos network.Likewise, in a 4-tiered Clos network, at most nine hops are needed for apacket to reach from one NVD to another NVD, where the source and targetNVDs are connected to the leaf tier of the Clos network. Thus, a Closnetwork architecture maintains consistent latency throughout thenetwork, which is important for communication within and between datacenters. A Clos topology scales horizontally and is cost effective. Thebandwidth/throughput capacity of the network can be easily increased byadding more switches at the various tiers (e.g., more leaf and spineswitches) and by increasing the number of links between the switches atadjacent tiers.

In certain embodiments, each resource within CSPI is assigned a uniqueidentifier called a Cloud Identifier (CID). This identifier is includedas part of the resource's information and can be used to manage theresource, for example, via a Console or through APIs. An example syntaxfor a CID is:

ocid1.<RESOURCE TYPE>.<REALM>. [REGION][.FUTURE USE].<UNIQUE ID>

where,ocid1: The literal string indicating the version of the CID;resource type: The type of resource (for example, instance, volume, VCN,subnet, user, group, and so on);realm: The realm the resource is in. Example values are “c1” for thecommercial realm, “c2” for the Government Cloud realm, or “c3” for theFederal Government Cloud realm, etc. Each realm may have its own domainname;region: The region the resource is in. If the region is not applicableto the resource, this part might be blank;future use: Reserved for future use.unique ID: The unique portion of the ID. The format may vary dependingon the type of resource or service.

FIG. 6 is a simplified block diagram of a distributed virtualizedenvironment 600 that may be hosted by CSPI provided by an IaaS cloudservice provider (CSP) and may include a VNICaaS system according tocertain embodiments. Distributed environment 600 comprises multiplesystems that are communicatively coupled via physical network or switchfabric 602. Physical network 602 may comprise multiple networkingdevices, such as multiple switches, routers, etc., that enablecommunications using protocols such as Layer-3 communication protocols.In certain implementations, physical network 602 may be an n-tiered Closnetwork as depicted in FIG. 5 and described above. The value of “n” maybe one, two, three, etc., depending upon the implementation.

Distributed environment 600 depicted in FIG. 6 is merely an example andis not intended to unduly limit the scope of claimed embodiments. Manyvariations, alternatives, and modifications are possible. For example,in some implementations, distributed environment 600 may have more orfewer systems or components than those shown in FIG. 6 , may combine twoor more systems, or may have a different configuration or arrangement ofsystems. The systems, subsystems, and other components depicted in FIG.6 may be implemented in software (e.g., code, instructions, program)executed by one or more processing units (e.g., processors, cores) ofthe respective systems, using hardware, or combinations thereof. Thesoftware may be stored on a non-transitory storage medium (e.g., on amemory device).

As shown in FIG. 6 , distributed environment 600 includes a host machine614 that may host one or more compute instances belonging to one or morecustomer VCNs. Host machine 614 is connected to NVD 606 via networkinterface card (NIC) 608. Host machine 614 is communicatively coupled toVNICaaS system 632 via NVD 606 and physical network 602.

In FIG. 6 , host machine 614 hosts a compute instance 610, which may bea virtual machine compute instance or a bare metal instance. Computeinstance 610 may be part of a customer VCN, where the VCN may includeone or more subnets and compute instance 610 belongs to one of thesubnets of the VCN. Compute instance 610 may participate in the VCN viamicro-VNIC 604 that is associated and configured for compute instance610 and the micro-VNIC is executed by NVD 606.

In certain implementations, a packet originating from compute instance610 is communicated from host machine 614 to NVD 606 via NIC 608. NVD606 executes software that is configured to provide functionalitycorresponding to micro-VNIC 604 associated with compute instance 610(also referred to as the NVD executing the micro-VNIC). Per theexecution of micro-VNIC 604, the packet is forwarded from NVD 606 toVNICaaS system 632 via physical network 602. VNICaaS system 632 isconfigured to process the packet and forward it to an endpoint basedupon the intended destination of the packet. In certain implementations,a tunneling protocol is used to communicate the packet from NVD 606 toVNICaaS system 632. VNICaaS system 632 may forward the packet to one ofmore of multiple endpoints, such as a gateway 634, a VNIC 636 associatedwith another compute instance 638, a VCN ritual router 640, or someother endpoint 642.

In certain implementations, micro-VNIC 604 is a special type of VNICthat is configured to perform only a small subset of the functionsperformed by a regular VNIC associated with a compute instance andexecuted by an NVD. In certain implementations, a micro-VNIC isconfigured to simply transfer packets received from compute instance 610to VNICaaS system 632 without processing the packets for security rulessuch as firewall rules, without performing any routing-relatedprocessing associated with identifying the destination of the packetsand finding next hops for the packets, or performing other traditionalVNIC-related functions. The micro-VNIC 604 acts as a pass-through tocommunicate the packets received by NVD 606 from compute instance 610 toVNICaaS system 632. A micro-VNIC may be configured and associated with aparticular compute instance (e.g., micro-VNIC 604 is associated withcompute instance 610) when the particular compute instance is added to aVCN.

While a micro-VNIC 604 is depicted in FIG. 6 , in other embodiments,other types of VNICs, including regular VNICs executed by NVDs andassociated with compute instances may be configured to act likemicro-VNICs and act as a bypass and forward packets to VNICaaS system632 for further processing. In certain implementations, a regular orstandard VNIC may be configured to act like a micro-VNIC and forward apacket to VNICaaS system 632 when certain conditions are met. Forexample, in the case of a regular or standard VNIC configured to have asits intended destination a service endpoint, then the standard VNIC mayalso forward traffic to the VNICaaS system 632 for processing purposes.

VNICaaS system 632 is configured to perform packet processing functionsfor packets received from multiple compute instances belongingpotentially to different VCNs, and belonging potentially to differentcustomers or tenants. In this manner, VNICaaS system 632 provides acentralized processing entity for providing dedicated packet processingservices for multiple compute instances belonging to multiple customersand belonging to multiple VCNs. VNICaaS system 632 includes a fleet ofcomputers that are dedicated to perform packet processing functions. TheVNICs-related packet processing performed by VNICaaS system 632 is notrestricted by the resources available to an NVD as in priorimplementations. This fleet of computers that constitute VNICaaS system632 can be scaled up (or down) as needed, providing for a highlyscalable (e.g., horizontally scalable) and highly available architecturefor processing from and to compute instances in distributed environment600. VNICaaS system 632 is capable of hosting multiple VNICs. The VNICshosted by VNICaaS system 632 are referred to as “service VNICs” (e.g.,service VNIC 618 depicted in FIG. 6 ) to differentiate them from themicro-VNICs and traditional VNICs associated with compute instances. Theprocessors of the fleet of computers that constitute VNICaaS system 632are configured to execute software and processes/threads to implementand execute the service VNICs functionality. While FIG. 6 depicts asingle service VNIC 618, this is not intended to be limiting. Typically,VNICaaS system 632 may execute or provide functionality for multipleservice VNICs for processing network traffic.

In certain implementations, the CSPI may provide various APIs, consoleinterfaces, etc., for configuring service VNICs and associatingmicro-VNICs (or regular VNICs) with service VNICs. For example, aservice may be created and associated with a particular micro-VNIC whenthe micro VNIC is created and associated with a compute instance. Thiscreation and association between compute instances, micro-VNICs, andservice VNICs may be provided and managed by the virtual cloud networkcontrol plane. For example, an API may enable creation of a service VNIC(e.g., service VNIC 618) that is associated with micro-VNIC 604, whichin turn is associated with compute instance 610. APIs may be provided tospecify metadata for a service VNIC, where the metadata includesinformation such as security or firewall rules for the service VNIC,forwarding rules, IP addresses associated with the service VNIC, and thelike. APIs may also be provided to enable modifications or changes tothe created service VNICs. For example, an API may be provided to add orremove IP addresses from a service VNIC, or to update a forwarding rulefor the IP address for the service VNIC. A forwarding rule for a serviceVNIC may specify how a packet that is to be processed according to theservice VNIC should be forwarded. In certain implementations, multipleVNICs (e.g., regular VNICs or micro-VNICs may be associated with thesame service VNIC).

In the embodiment depicted in FIG. 6 , VNICaaS system 632 includes a Topof Rack switch (TOR) 616 that is connected to multiple data processingsystems or host machines 619 including machines 626, 628, 630. The TORswitch 616 receives packets that are forwarded to VNICaaS system 632 forpacket processing. TOR switch 616 is then configured to select, from themultiple host machines that are connected to TOR switch 616 and that areavailable for packet processing, a particular host machine forprocessing the received packet. For example, TOR switch 616 depicted inFIG. 6 may select one of host machines 626, 628, and 630 for processinga packet originated by compute instance 610 and forwarded to VNICaaSsystem 632 by NVD 606. While three host machines 626, 628, and 630 areshown in FIG. 6 as being part of VNICaaS system 632, this is notintended to be limiting. In alternative embodiments, a VNICaaS systemmay have more or less than three host machines. The set of host machines619 work together to provide a highly-available environment withadequate bandwidth to process large volumes of network trafficcommunicated between virtual networks in distributed environment 600.

The host machine selected by the TOR switch is then responsible forfurther processing of the packet. Each host machine comprises compute(e.g., one or multiple processors), storage (e.g., system memory andstorage), and networking resources that are available for packetprocessing performed by the host machine. In certain implementations, aset of multiple processes or threads is configured on each host machinefor processing packets received by the host machine. For example, asdepicted in FIG. 6 , a set of worker threads 620 is available on hostmachine 626 to process packets received by host machine 626 forprocessing from TOR switch 616. In a similar manner, a set of workerthreads 622 is configured and available for host machine 628, and a setof worker threads 624 is configured for and available for processingperformed by host machine 630.

Upon receiving a packet for processing from the TOR switch, a hostmachine is configured to select an available worker thread, from the setof worker threads configured for that host machine, for processing thepacket. In certain implementations, the selected worker thread isconfigured to examine the received packet (e.g., one or more headers ofthe packet) and determine a service VNIC for processing the packet. Incertain embodiments, the service VNIC is selected based upon informationidentifying the sender of the packet. For example, in FIG. 6 , for apacket received from compute instance 610 via NVD 606, the header of thereceived packet may identify one or more of the sender compute instance610, the NVD 606 from which the packet is received, and the micro-VNIC604. Based upon this information, the host machine may select aparticular service VNIC for processing the packet. For example, theselected service VNIC may be one that is associated with micro-VNIC 604.

The packet is then processed by the worker thread according to theselected service VNIC. For example, the selected VNIC may haveassociated metadata that specifies security and firewall rules,forwarding rules, routing protocols, etc. The worker thread executesfunctionality for selected service VNIC by enforcing the rulesassociated with the service VNIC. For example, the worker thread maydetermine, based upon the security or firewall rules, if communicationof the packet to its intended destination (i.e., the destination addressspecified in the packet) is allowed or not. The enforcement of thesevarious rules, which in previous architectures was executed by the NVDexecuting a VNIC associated with a compute instance, is now insteadexecuted by VNICaaS system 632.

As part of the processing performed by a worker thread, the workerthread is configured to identify a next-hop target to which the packetis to be sent. In certain implementations, the next hop target isdetermined based upon the destination of the packet and based uponrouting rules specified by the service VNIC that is selected forprocessing the packet. The worker thread is then configured to send thepacket to the determined next-hop target. Examples of next-hop targetsinclude without limitation a gateway 634, another VNIC 636 associatedwith a compute instance 638, a VCN virtual router 640, or some othernext-hop target 642. The next hop that is selected is one thatfacilitates communication of the packet to its intended destination, forexample, the next-hop target may then forward the packet to itsdestination. For example, if the destination for a packet from computeinstance 610 is a compute instance 638, an NVD hosting VNIC 636associated with compute instance 638 may be identified by the workerthread as the next hop and the packet may be forwarded to that NVD.

As depicted in FIG. 6 , a gateway 634 may be selected as a next-hoptarget based upon the intended destination of the packet. There could bedifferent kinds of gateways based upon the destinations. Examples ofgateways have been described above and may include a Dynamic RoutingGateway (DRG), Network Address Translation (NAT) gateway, Private AccessGateway (PAGW), a service gateway (SGW), or any other types of gateways.

FIG. 7 is a simplified block diagram of a distributed environment 700that includes a VNICaaS system and builds upon the distributedenvironment depicted in FIG. 6 . As shown in FIG. 7 , distributedenvironment 700 includes several components from FIG. 6 , which arenumbered using the same reference numbers as in FIG. 6 . Additionally,distributed environment 700 includes a host machines 710 that hostscompute instance 704, which is associated with micro-VNIC 712. Computeinstance 610 via its associated micro-VNIC 604 and compute instance 704via its micro-VNIC 712 may be members of the same customer VCN. Thecompute instances may be on the same or different subnet of the VCN. Asshown in FIG. 7 , host machine 710 is connected to NVD 714 via networkinterface card (NIC) 702. Host machine 710 is communicatively coupled toVNICaaS system 632 via NVD 714 and a physical network (not shown) suchas physical network 602.

In certain implementations, a packet originating from compute instance704 is communicated from host machine 710 to NVD 714 via NIC 702. NVD714 executes software that is configured to provide functionalitycorresponding to micro-VNIC 712 associated with compute instance 704. Asa result of micro-VNIC 712, the packet is forwarded from NVD 714 toVNICaaS system 632. VNICaaS system 632 is then configured to process thepacket and forward it to an endpoint based upon the intended destinationof the packet.

In the implementation depicted in FIG. 7 , both micro-VNICs 604 and 712are associated with service VNIC 618. Accordingly when packets from thecompute instances are received by VNICaaS system 632, the same serviceVNIC 618 is selected for processing the packets. This is an example of asituation where packets originating from different compute instances areprocessed by VNICaaS system 632 using the same service VNIC 618. Thiswas not possible in previous implementations in which there was aone-to-one correspondence between compute instances and VNICs used toroute packets from the compute instances. This is one way in whichservice VNICs hosted by VNICaaS system 632 provide scaling of VNICs.

In certain implementations, service VNIC 618 is a scalable interfacethat can be positioned in front of a service that is running behind agateway or collection of hosts. Different cloud services may be frontedby one or more service VNICs 618. The service VNIC 618 presents aconfiguration attachment point for customers where the security androuting policy can be specified that should be applied to traffic to andfrom that service VNIC 618.

FIG. 8 depicts a simplified flowchart 800 illustrating processing ofpackets using a VNICaaS system according to certain embodiments. Theprocessing depicted in FIG. 8 may be implemented in software (e.g.,code, instructions, program) executed by one or more processing units(e.g., processors, cores) of the respective systems, using hardware, orcombinations thereof. The software may be stored on a non-transitorystorage medium (e.g., on a memory device). The method presented in FIG.8 and described below is intended to be illustrative and non-limiting.Although FIG. 8 depicts the various processing steps occurring in aparticular sequence or order, this is not intended to be limiting. Incertain alternative embodiments, the processing may be performed in somedifferent order or some steps may also be performed in parallel.

As depicted in FIG. 8 , processing is initiated in 805, wherein a sourcecompute instance on a host machine originates a packet to becommunicated to a destination endpoint. The source compute instance maybe part of a subnet of a customer VCN. For example, in FIG. 6 , computeinstance 610 hosted by host machine 614 may originate a packet destinedfor compute instance 638.

At 810, the packet is forwarded from the host machine hosting theoriginating compute instance, via a NIC on the host machine, to a NVDimplementing a VNIC associated with the originating compute instance.For example, in FIG. 6 , the packet is communicated from host machine614, via NIC 608 of host machine 614, to NVD 606 connected to hostmachine 614, and which executes micro-VNIC 604 associated with computeinstance 610.

At 815, the receiving NVD executes the micro-VNIC associated with theoriginating compute instance and forwards the packet to the VNICaaSsystem. For example, in FIG. 6 , as a result of micro-VNIC 604, thepacket is forwarded from NVD 606 to VNICaaS system 632. The packet isprocessed by VNICaaS system 632.

In certain implementations, a tunneling protocol is used to communicatethe packet from NVD 606 to VNICaaS system 632. Various differenttunneling protocols may be used such as IP-in-IP (or Generic RoutingEncapsulation (GRE)), Virtual Extensible LAN (VxLAN—IETF RFC 7348),Virtual Private Networks (VPNs) (e.g., MPLS Layer-3 Virtual PrivateNetworks (RFC 4364)), VMware's NSX, GENEVE (Generic NetworkVirtualization Encapsulation), and others. Tunneling typically involvesencapsulating the received packet in one or more headers and theinformation in the headers is used to communicate the packet from theNVD to the VNICaaS system via a physical substrate network. Tunneling ina virtualized network enables traffic to be communicated from one endpoint (e.g., the NVD sending a packet) to another end point (e.g.,VNICaaS system) without making any changes to the original packetreceived by the sending NVD. Processing related to encapsulating thepacket are performed by the sending NVD. For example, in FIG. 6 , thepacket encapsulation is performed by NVD 606. Operations pertinent topacket processing e.g., encapsulation, mapping, etc., are describedlater with reference to FIGS. 11A-11C.

At 820, the packet sent by the NVD is received by a TOR switchassociated with the VNICaaS system. For example, in FIG. 6 , the packetsent by NVD 606 may be received by TOR switch 616.

At 825, the TOR switch receiving the packet in 820 uses a selectiontechnique to select a particular host machine from multiple availablehost machines in the VNICaaS system for processing the packet, and thenforwards the packet to the particular selected host machine. Variousdifferent selection techniques may be used by the TOR switch forselecting a particular host machine for processing the packet. Incertain implementations, the TOR switch uses Equal-Cost Multi-Path(ECMP) processing to select a particular host machine for processing thepacket. For example, in FIG. 6 , TOR 616 may use ECMP to select one ofhost machines 626, 628, and 630 for processing the received packet. Asan example, it is assumed the TOR switch 616 selects host machine 628for processing the packet and forwards the packet to the selected hostmachine.

At 830, on the particular host machine selected in 825 and that receivesthe packet from the TOR switch, a particular worker thread is selectedfor processing the packet from among multiple available worker threadsconfigured and executing on the host machine for processing packets. Forexample, in FIG. 6 , host machine 628 may select one of worker threads622 for processing the packet.

In step 835, the worker thread selected in 830 identifies a particularservice VNIC for processing the packet from among multiple service VNICshosted by the VNICaaS system for processing packets. For example, inFIG. 6 , the worker thread may identify, for example, service VNIC 618for processing the packet.

Various different ways may be used for selecting a service VNIC. Incertain embodiments, the particular service VNIC is selected based uponinformation in the packet. For example, in some instances, theparticular service VNIC may be selected based upon information in thepacket header regarding the source of the packet. For example, thepacket may have a header that includes labels identifying source anddestination information for the packet. The source label may, forexample, identify the source VNIC from which the packet was received(e.g., micro-VNIC 604 in FIG. 6 ) and a destination label may identify adestination for the packet (e.g., a destination VNIC such as VNIC 636 inFIG. 6 ).

In certain instances, the service VNIC may be selected in 835 based uponthe source label information. For example, the source VNIC may beidentified from the packet. A search may then be performed to find aservice VNIC associated with the source VNIC and that service VNIC isselected in 835. As previously indicated, the association between a VNICand a service VNIC may be configured when the compute instance isassociated with the VNIC. This association or mapping may be stored asconfiguration information accessible to the VNICaaS system. Thisinformation may be generated by the VCN control plane.

In some other instances, the service VNIC may be selected based upon theinformation in the destination label of the packet. For example, if thedestination label identifies a PE-VNIC or a VNIC associated with aparticular service or service instance, a service VNIC associated withthat PE-VNIC or VNIC may be selected in 835 for processing the packet.In yet other instances, the information in the packet header identifyingthe source of the packet (e.g., information in the source label) andinformation identifying the destination of the packet (e.g., informationin the destination label) may be used for selecting a particular serviceVNIC to be used for processing the packet.

As previously indicated, a service VNIC may have metadata associatedwith it where the metadata identifies one or more policies identifyingvarious rules such as security or firewall rules, forwarding or routingrules controlling how a packet is to be forwarded, and other rules. At840, one or more policies and rules specified for the service VNICidentified in 835 are determined. In certain implementations, theservice VNICs and the associated policies may be stored in a memorylocation accessible to the host machine that receives the packet forprocessing.

At 845, the worker thread processing the packet applies the one or morepolicies associated with the selected service VNIC, and further basedupon the destination information for the packet (e.g., destinationinformation in the IP packet header), identifies a next-hop target forthe packet. Examples of net hop targets include a gateway, another VNICassociated with a compute instance to which the packet is directed, andthe like. For example, in FIG. 6 , if the destination of the packet iscompute instance 638, the VNIC 636 associated with the compute instancemay be identified as the next hop target in 845.

At 850, the particular worker thread processing the packet then causesthe packet to be forwarded to the next-hop target determined in 845. Incertain implementations, the worker thread may update a header of thepacket prior to forwarding the packet to the next-hop target.

In certain instances, it is possible that, in 845, multiple next hoptargets are identified for the packet. This may happen, for example,when multiple micro-VNICs are identified as targets by the service VNICselected for processing the packet. In such a situation, one of themultiple next hop targets is selected in 845 and then, at 850, thepacket is forwarded to that selected target. This selection of onetarget from among multiple identified targets may enable the VNICaaSsystem to distribute packets across the multiple identified targets andthus perform load balancing of the traffic across the multiple targets.Various different techniques may be used to select a single next hoptarget from among multiple identified next hop targets.

FIG. 9 is a simplified block diagram depicting components within aVNICaaS system according to certain embodiments. FIG. 9 depictscomponents of VNICaaS system 632 depicted in FIG. 6 . The configurationof VNICaaS system 632 depicted in FIG. 9 is merely an example and is notintended to unduly limit the scope of claimed embodiments. Manyvariations, alternatives, and modifications are possible. For example,in some implementations, VNICaaS system 632 may implemented having moreor fewer systems or components than those shown in FIG. 9 , may combinetwo or more systems, or may have a different configuration orarrangement of systems. The systems, subsystems, and other componentsdepicted in FIG. 9 may be implemented in software (e.g., code,instructions, program) executed by one or more processing units (e.g.,processors, cores) of the respective systems, using hardware, orcombinations thereof. The software may be stored on a non-transitorystorage medium (e.g., on a memory device).

As depicted in FIG. 9 , VNICaaS system 900 comprises a TOR switch 616that is connected to a set of host machines 619, including host machines626 and 628. TOR switch 616 includes an ECMP subsystem 910 that isconfigured to perform ECMP processing to select one of host machines 619for processing a packet received by the TOR switch. The ECMP protocolmay rebalance load as needed between available VNICaaS host machines,and also as one or more host machines are added or removed from VNICaaSsystem. VNICaaS system may advertise a Virtual Internet Protocol (VIP)address via Border Gateway Protocol (BGP). Packets addressed to that VIPaddress are received by TOR switch 616 and then forwarded to one of thehost machines 619 for further processing. The host machines 619 providea highly-available environment with adequate bandwidth to processnetwork packets.

In certain embodiments, the VNICaaS host machines may advertise theiraddresses via Border Gateway Protocol (BGP) to the TOR switch. The TORswitch 616 may then use ECMP protocol processing to identify a specificVNICaaS host machine from the multiple host machines advertised overBGP. In some implementations, the VNICaaS host machines may advertisemultiple IP addresses corresponding to multiple tasks to be performed bythe host machines. The TOR switch 616 may classify incoming packetsbased on the configured tasks to be performed on the packets andrelevant IP addresses associated with host machines for performing thosetasks.

In some implementations, a VNICaaS host machine (e.g., host machines 626and 628) may contain a NIC, one or more CPUs, system memory (e.g., RAM)that may be communicatively coupled to each other via one or more systembuses. For example, in FIG. 9 , host machine 626 comprises a NIC 935, aCPU 915, and system memory 920, and host machine 628 comprises a NIC960, a CPU 945, and system memory 940. Various software components maybe stored and/or executed by the CPU of a host machine in the hostmachine's system memory. For example, in FIG. 9 , the components includea set of worker threads, a Core Packet processor (CPP), and one or moreprocessing agents. Using host machine 626 as an example, system memory920 includes a set of worker threads including workers 620, 621, a CPP925, and agents 930. Host machine 628 comprises a system memory 940executing a set of worker threads including threads 622 and 623, a CPP950, and agents 955.

In some implementations, the Core Packet processor (CPP) of a hostmachine works in conjunction with the worker threads and is configuredto process and forward the traffic received by the host machine 626 forprocessing. In certain implementations, CPP 925 may be a multi-threadedData Plane Development Kit (DPDK) application that processes the networktraffic. In an example embodiment, the CPP may include a plurality ofpipelines for forwarding traffic from a compute instance to a target oran endpoint, and forwarding traffic from the endpoint to the computeinstance. The CPP may use or include a number of identical workersthreads (e.g., worker thread 620, worker thread 621, etc.) to processand forward traffic. In certain implementations, the CPP may flow-hashthe incoming packets and then select a particular worker thread toprocess the packet, such that packets are evenly distributed and loadbalanced between the available worker threads. A worker thread thenprocesses the packet including selecting a service VNIC, determiningpolicies for the selected service VNIC, finding a next hop target, andforwarding the packet to the identified next hop target, as describedabove with respect to FIG. 8 . In certain implementations, a worker canover time process packets using multiple service VNICs. Accordingly, thesame worker thread can be used to process multiple packets usingmultiple service VNICs.

In an alternative implementation, the CPP may analyze a received packetand identify a specific worker thread to send the packet to be forwardedto its destination. In some implementations, the 0^(th) worker thread(e.g., thread 620) may handle periodic housekeeping tasks such asaccumulating metrics.

As indicted above, a host machine in VNICaaS system 900 may comprise oneor more agents to support processing of network packets. For example, inFIG. 9 , host machine 626 contains agents 930 executing in system memory920, and host machine 628 contains agents 955 executing in system memory940. The one or more agents may include a configuration agent. Aconfiguration agent may be configured to ingest a VCN configuration fromVCN control plane. The configuration agent may provide configurationinformation required to process packets from the VCN control plane,including: IP address assignments, security rules, route rules, otherVNIC locations, etc.

The one or more agents may further include an Address ResolutionProtocol (ARP) agent that monitors the TOR and sets up a layer 2 MediaAccess Control (MAC) address for a CPP. The one or more agents mayinclude a State Replication Agent (SRA agent) that implements adistributed key-value storage of network state used by the CPP fordistributed connection tracking. The one or more agents may include aBGP agent which advertises IP addresses associated with the VNICaaS hostmachines to the TOR via BGP.

In some implementations, the compute, memory, and networking resourcesof a VNICaaS system host machine may be organized or divided intomultiple nodes. In a specific implementation, a VNICaaS host machinecomprises two nodes, each node comprising of a CPU socket, a RAM, and aNIC. In this implementation, the NIC may present two

endpoints for the VNICaaS host machine. In such an embodiment, forpackets received by the host machine, internally, the NIC of the hostmachine load-balances approximately half its traffic onto each of thePCI endpoints corresponding to the two nodes. A virtual functionprovides routing to and from one of the PCI endpoints.

In some implementations, a high-performance multi-threaded application(e.g., DPDK application) may be bound to a CPU (CPU socket) of eachnode. The application may not cross the domain of a node. Specifically,the multi-threaded application worker threads that provide VNICsfunctionality may be scheduled on the same node as the network card. Adriver may support up to 16 workers or VNICs per a Virtual Local AreaNetwork (VLAN). In some implementations, a VNICaaS host machine mayutilize both nodes by instantiating two data planes, where each node isprovided with a separate set of regional configuration from the dataplane. Accordingly, a VNICaaS host machine can support two instances ofthe VCN data plane (one running on each node).

In some implementations, a VNICaaS host machine may also include amanagement port. The management port may allow for common managementoperations to be performed such as, software deployment to host machine,OS patching on the host machine, operator access to the host machine formaintenance or troubleshooting, etc.

FIG. 10 depicts distributed environment 1000 comprising a VNICaaS systemand the flow of packets for a particular use case between a customer'svirtual cloud network and a service provider's virtual cloud networkusing the VNICaaS system, according to certain embodiments.Specifically, the use case depicted in FIG. 10 relates to sendingpackets from a customer compute instance in a customer VCN to a computeinstance implementing a service (referred to as a service computeinstance or service instance) using a VNICaaS system, where the serviceinstance is exposed via a private endpoint in the customer's VCN.

As previously described, a service provider can provide a service usingone or more compute instances hosted by CSPI. The provided service maybe consumed by one or more subscribing customers of the service.Different access models may be used to provide access to the service.According to a public access model, the service may be exposed as apublic endpoint that is publicly accessible by compute instances in acustomer VCN via a public network such as the Internet. According to aspecific private access model, the service is made accessible as aprivate IP endpoint in a private subnet in the customer's VCN. This isreferred to as a Private Endpoint (PE) access and enables a serviceprovider to expose their service as an instance in the customer'sprivate network. A Private Endpoint resource represents a service withinthe customer's VCN. Each PE manifests as a VNIC (referred to as aPE-VNIC, with one or more private IPs) in a subnet chosen by thecustomer in the customer's VCN. A PE thus provides a way to present aservice within a private customer VCN subnet using a PE-VNIC. Since theendpoint is exposed as a VNIC, all the features associated with a VNICsuch as routing rules, security lists, etc., are now available for thePE VNIC.

For the example embodiment depicted in FIG. 10 , it is assumed that apacket is to be communicated from a compute instance 610 within acustomer's VCN to a service compute instance 1030 within a service VCN1020, where the service endpoint is exposed as a PE-VNIC within thecustomer VCN. Compute instance 610 may initiate a connection to thePE-VNIC 618 by generating a packet whose destination is the PE-VNIC.

In certain implementations, a service VNIC 618 corresponding to thePE-VNIC is hosted by VNICaaS system 632 that enables service providersto expose their service as a private instance in the customer's privatenetwork. Private Endpoint VNIC (or PE-VNIC) is a virtual networkingfeature enabling a customer access to multi-tenanted services hosted inother VCNs via a private access point whose configuration is under thecustomer's control. Specifically, a PE-VNIC represents a serviceassociated with the compute instance 1030 within the service provider'sVCN 1020. To a customer (e.g., customer instance 610), the PE-VNICappears as a private endpoint in the same VCN as compute instance 610and where the endpoint appears “attached” to the service with which thecustomer wishes to interact. To a service provider (e.g., computeinstance 1030), PE-VNIC appears to be a gateway to (and from) which alltraffic to customer VCNs flows.

In FIG. 10 , a packet may be originated by compute instance 610 hostedby host machine 614, where the compute instance 610 is part of a subnetwithin a customer's VCN. The destination of the packet is the PE-VNIC.The packet may be communicated from host machine 614 to NVD 606 via NIC608. On NVD 606, a micro-VNIC 604 associated with compute instance 610is executed and the packet sent from NVD 606 to VNICaaS system 632. Thepacket may be sent VNICaaS system 632 using a tunneling protocol. Insome embodiments, the IP address of the PE-VNIC corresponds to thevirtual IP address or anycast address of VNICaaS system 632 and thepacket is forwarded to the VNICaaS system 632. The packet may becommunicated to VNICaaS system 632 by using anycast IP addressassociated with the VNICaaS system and overlay IP address for thePE-VNIC.

Tunneling the packet from NVD 606 to VNICaaS system 632 includesencapsulating the packet using one or more headers, wherein the headerinformation is used to forward the packet to VNICaaS system 632. Thevarious headers and their contents to perform the tunneling is shown inFIGS. 11A-11C and described below.

At VNICaaS system 632, the packet is received by TOR switch 616. In someembodiments, the packet includes a header comprising a source VNIC labelidentifying micro-VNIC 604 and a destination VNIC label identifying thePE Label or PE-VNIC. Within VNICaaS system 632, TOR switch 616 selects ahost machine for processing the packet and the packet is transmitted tothe selected host machine. On the host machine receiving the packet, aworker thread is selected for processing the packet from among multipleworker threads available on the selected host machine, as describedabove with respect to FIG. 8 .

In certain implementations, the selected worker thread then performs thefollowing processing:

(1) The worker thread identifies a destination IP address of the packet.Typically, network traffic is transmitted in the form of packets, whereeach packet includes a header and a payload. The header containsinformation regarding the source address, destination address, size,transport protocol used to transmit the packet, and various otheridentification information associated with the packet of data.

(2) The worker thread validates the destination IP address of the packetdetermined in (1) to ensure that the IP address is an AvailabilityDomain (AD), regional or an anycast IP address associated with aservice. An anycast IP address is an IP address that is associated withmultiple machines within the service VCN 1020.

(3) The worker thread selects a service VNIC for processing the packetbased on header information of the packet. In certain embodiments, theworker thread identifies a destination MPLS label from the packet andselects a VNIC based upon the MPLS label. Since the packet is directedto a PE-VNIC, the selected service VNIC is one corresponding to thePE-VNIC where the packet is to be sent. The worker thread obtainsmetadata and configuration information of the PE-VNIC such as differentpolicies associated with the service VNIC.

(4) The worker thread validates micro-VNIC (e.g., micro-VNIC 604) thatwas associated with compute instance sending the packet. In this step,the worker thread verifies that the substrate source IP address of thepacket refers to the NVD of the associated micro-VNIC, for example, thephysical IP address of NVD 606.

(5) The worker thread validates ingress firewall rules associated withthe selected service VNIC for service VCN 1020. The ingress firewallrules specify the types of traffic (e.g., protocols and ports) that areallowed in and out of a compute instance 1030 within the service VCN1020. A given rule may be stateful or stateless. For example, incomingsecure shell (SSH) traffic from anywhere can access a set of instancesby setting up a stateful ingress rule with source CIDR 0.0.0.0/0 and adestination Transmission Control Protocol (TCP) port.

(6) The worker thread identifies a next hop target for the packet. Forexample, the next hop target may be PAGW 1010 associated with serviceVCN 1020.

(7) The worker thread de-capsulates the packet by removing encapsulatedheader of the packet and then encapsulates the packet with MPLS labelswhere a source MPLS label is set to the PE-VNIC label and destinationlabel is set based upon the next hop target determined in (6). Forexample, the destination label may identify the receiving gateway. Incertain implementations, the source may be set to the VNICaaS system'sIP address (e.g., anycast IP address) and destination of the packet maybe set to data plane IP address (e.g., anycast IP address) associatedwith the destination service. The packet may then be forwarded to theanycast IP address associated with the service.

In certain implementations, the data plane associated with the servicefurther may encapsulate the packet with substrate information associatedwith the compute instance 1030 and send the packet to a load balancerwithin the service VCN 1020. The data plane may be a “gateway” that doessome packet processing before the service load balancer receives thepacket. The load balancer then processes the packet and sends the packetto the destination compute instance 1030.

In one embodiment, as shown in FIG. 10 , the packet may be communicatedfrom VNICaaS system 632 to Private Access Gateway (PAGW) 1010. A PAGW1010 is a type of a service gateway attached to a service provider VCN1020 that acts as an ingress/egress point for all traffic from/toconsumer endpoints. The PE-VNIC endpoint comprises information used fortunneling packets to and from the PAGW 1010. In this scenario, a tunnelis designed to forward traffic between VNICaaS system 632 and PAGW 1010.In an example embodiment, an implementation of PE-VNIC may involveVNICaaS hosts and Private Access Gateway (PAGW) 1010 hosted on adedicated compute resources.

In certain implementations, a PE-VNIC that is implemented by a serviceVNIC hosted on VNICaaS system 632 does not have a compute instanceattached to the PE-VNIC but instead acts as a tunnel to the PAGW, whichin turn forwards traffic to the corresponding service provider (e.g.,compute instance 1030). This arrangement enables a service provider touse the PE-VNIC for multiple backend compute instance connectionswithout utilizing internal IP address resources of the service VCN. Asingle PAGW can be provided for any number of service endpointsregistered in a single VCN. In a certain implementation, both thePE-VNIC and the PAGW may be hosted on a dedicated compute resource inVNICaaS system 632.

In the above scenario, a substrate tunnel may be used to forward trafficbetween VNICaaS host machine and PAGW host machines. In certainimplementations, the substrate tunnel is implemented using MultiprotocolLabel Switching (MPLS) over User Datagram Protocol (UDP). MPLS over UDPmay facilitate the load balancing of MPLS application traffic across IPnetworks. In the above scenario, the MPLS over UDP enables VCNhost-to-host encapsulation format for forwarding the traffic.

In certain embodiments, VNICaaS host machines 619 may classify trafficby knowing a relevant Virtual IP address (VIP) for the PAGW. If VNICaaSdoes not classify the traffic directed to PAGW then the traffic may betreated as a two-label tunnel traffic. The two-labels of a networkpacket may be a channel number and a group number to further classifythe packets and their destinations. The first label indicates thesending VNIC (e.g., service VNIC 618 corresponding to the PE-VNIC) andthe second label indicates the instance of PAGW receiving the traffic.

In the above embodiment, a CPP within a VNICaaS host may providemultiple instances of pipelines to forward traffic from PE-VNICpresented to a customer to PAGW tunnel. In the above scenario, theservice VNIC implementing the PE-VNIC may be identified using a slotidentifier for VNICs unlike traditional VNICs which are identified byunique NAT IP addresses. The slot identifier may act as an index toidentify VNICs hosted on the VNICaas system 632.

A service instance 1030 receiving a packet from a compute instance(e.g., compute instance 610) may respond by communicating a responsepacket to customer instance 610. In certain implementations, VNICaaSsystem 632 facilitates communication of the response packet from servicecompute instance 1030 to compute instance 610.

In certain implementations, VNICaaS system 632 also stores informationabout the different traffic flows processed by VNICaaS system 632. Forexample, for a packet communicated from compute instance 610 to servicecompute instance 1030, VNICaaS system 632 (or more particularly, thehost machine that was selected to process the packet) may first identifya particular traffic flow to which the packet belongs. This may be doneby hashing the contents of one or more fields of the packet and thegenerated hash value represents a particular network traffic flow. In aspecific example, the contents of the source IP, source port,destination IP, destination port, and protocol fields of the packet arehashed. State information is then stored by VNICaaS system 632 for theparticular identified network flow, where the state information includesinformation such as the physical IP address of the NVD sending thepacket (e.g., physical IP address of NVD 606), the source anddestination information for the packet, and the like. This informationmay be stored in a flow table. Replication techniques may be used toreplicate the flow table information to the various host machines inVNICaaS system 632 so that information regarding the various trafficflows and their state information is available to all the VNICaaS systemhost machines irrespective of which particular host machine processedthe particular packet from compute instance 610 to compute instance1030.

Upon receiving a response packet at VNICaaS system 632, a host machinewithin VNICaaS system 632 may be selected for processing the packet, andfurther a worker thread from multiple worker threads executed by theselected host machine may be selected for processing the responsepacket. In an example embodiment, the VNICaaS system host machineselected to process the response packet may be different from theVNICaaS host machine that processed the packet sent from computeinstance 610 and compute instance 1030. In an example implementation,the following steps are performed by the worker thread to process andforward the response packet to NVD 606 associated with the customerinstance 610:

(1) The worker thread hashes portions (e.g. contents of certain headerfields) of the response packet to obtain a hash value that represents aparticular traffic flow. For example, the source IP, source port,destination IP, destination port, and protocol fields of the responsepacket may be hashed.

(2) The worker thread then consults a flow table and determines stateinformation for the particular traffic flow, where the state informationidentifies the physical IP address of an NVD associated with the NVDcorresponding to the destination compute instance i.e., the intendeddestination of the reverse flow packet.

(3) The worker thread may perform some validations. For example, theworker thread may validate that the destination IP address is anAvailability Domain IP address, a regional IP address or an anycast IPaddress within customer's virtual network.

(4) The worker thread then encapsulates the packet to prepare it to becommunicated from the VNICaaS system to the NVD associated with thephysical IP address determined in (2). As part of the processing in (4),the worker thread identifies the destination MPLS label from theresponse packet. The worker thread encapsulates the response packet withupdated source and destination information. The substrate source anddestination IP address are updated where the source IP is set to theanycast IP address of VNICaaS system 632 and the destination IP is setto the physical IP address of the receiving NVD 606 determined in (2).

(5) The response packet is then communicated from VNICaaS system 632 toNVD 606 using a tunneling protocol.

(6) The receiving NVD then forwards the response packet to computeinstance 610, which is the intended destination of the response packet.

FIGS. 11A-11C depict an example of encapsulation techniques that areused to communicate a network packet from a customer's compute instanceto a VNICaaS system according to certain embodiments. For the exampledepicted in FIGS. 11A-11C it is assumed that a packet is sent from acompute instance (e.g., compute instance 610 depicted in FIG. 10 ) to aservice exposed by a PE-VNIC. FIG. 11A depicts the original packet thatis originated by compute instance 608 and communicated to NVD 606. Asshown in FIG. 11A, the packet includes several fields including fieldsstoring information identifying a source IP address, a destination IPaddress, protocol information, a source port, and a destination port.The source IP address of the packet is set to the overlay IP address ofcompute instance 610, which is an IP address associated with themicro-VNIC 604 associated with compute instance 610. The destination IPaddress is set to that of the PE-VNIC. The source port is set to theclient port associated with the compute instance and the destinationport is set to a service port associated with the service. The protocolfield is set to TCP.

NVD 606 executes functionality corresponding to micro-VNIC 604 andencapsulates the packet to prepare it to be communicated to VNICaaSsystem 632. As part of the encapsulation, as shown in FIG. 11B, a headeris added to the original packet, where the header has the followingfields: (a) a source IP field that is set to the physical IP address ofNVD 606;

-   -   (b) a destination IP field that is set to anycast IP address for        VNICaaS system 632. The anycast IP address of VNICaaS system 632        may be obtained as part of configuration from the VCN control        plane; (c) a source MPLS label identifying the micro-VNIC 604        associated with compute instance 610; and (d) a destination MPLS        label identifying the PE-VNIC as the destination endpoint.

The packet is then communicated to VNICaaS system 632 using a tunnelingprotocol, where the header added by NVD 606 is used to communicate thepacket from NVD 606 to VNICaaS system 632 over a physical network 602.

At VNICaaS system 632, the packet is forwarded to a particular hostmachine and a particular worker thread executed by the selected VNICaaShost machine then processes the packet as described. The worker threadmay determine that the next hop target for the packet is an anycastaddress associated with the service exposed by the PE-VNIC. The workerthread updates the header information in the packet such that: thesource IP address is set to the anycast IP address of VNICaaS 632; thedestination substrate IP address is set to an anycast IP addressassociated with the service; the source label is set to PE-VNIC; and thedestination label is set to the PE label. Using the encapsulated header,the packet is forwarded to its destination (e.g., compute instance1030).

FIGS. 12A-12C depict an example of encapsulation performed for aresponse packet to be communicated from a service compute instance(e.g., compute instance 1030 in FIG. 10 ) to a customer's computeinstance (e.g., compute instance 610 in FIG. 10 ) according to certainembodiments. FIG. 12A shows the encapsulation for the response packetcommunicated from the service endpoint to VNICaaS system 632. Theresponse packet includes an original response packet and a header thatis added to the original response packet. The original response packetfields are as follows: Source IP—set to the PE VNIC IP; DestinationIP—set to the overly IP address of compute instance 610; Protocol—set toTCP; Source port—set to service port; Destination port—set to clientport.

The header that is added to the response packet to enable it to becommunicated to VNICaaS system 632 has the following information: SourceIP—set to anycast address associated with the service; DestinationIP—set to the anycast IP address associated with VNICaaS system 632;Source MPLS label—set to PE (private endpoint) label associated with theservice; Destination MPLS label—set to PE VNIC (identifying the serviceVNIC corresponding to the PE-VNIC).

Once the second packet is received by VNICaaS host 632, processing isperformed and it is determined that the response packet is to beforwarded to a physical IP address associated with NVD 606. Tofacilitate communication of the response packet from VNICaaS system 632to NVD 606 using a tunneling protocol, the header information in thepacket is changed as follows: Source IP—set to anycast addressassociated with VNICaaS system 632; Destination IP—set to the physicalIP address of NVD 606; Source MPLS label—set to PE VNIC; DestinationMPLS label—set to micro-VNIC 604 associated with compute instance 610.

The packet is communicated from VNICaaS system 632 to NVD 606 using atunneling protocol. Upon receiving the response packet, NVD 606de-capsulates the response packet (i.e., removes the header added to theresponse packet for tunneling purposes) and forwards the response packetto compute instance 610. FIG. 12C depicts the response packet receivedby compute instance 610.

FIG. 13 depicts a simplified flowchart 1300 depicting processingperformed for communicating a response packet using a VNICaaS systemaccording to certain embodiments. The processing depicted in FIG. 13 maybe implemented in software (e.g., code, instructions, program) executedby one or more processing units (e.g., processors, cores) of therespective systems, using hardware, or combinations thereof. Thesoftware may be stored on a non-transitory storage medium (e.g., on amemory device). The method presented in FIG. 13 and described below isintended to be illustrative and non-limiting. Although FIG. 13 depictsthe various processing steps occurring in a particular sequence ororder, this is not intended to be limiting. In certain alternativeembodiments, the processing may be performed in some different order orsome steps may also be performed in parallel. In the embodiment depictedin FIG. 10 , the method depicted in FIG. 13 may be used to communicate aresponse packet from service compute instance 1030 to compute instance610.

The processing in FIG. 13 assumes that a packet has previously beencommunicated from one compute instance to another compute instance usinga VNICaaS system. For sake of example, the packet may have beencommunicated from compute instance 610 to compute instance 1030 depictedin FIG. 10 , and a response packet is being sent in response to thatprevious communication.

At 1305, a response packet is originated at a sender compute instance tobe communicated to a destination compute instance. For example,referring to FIG. 10 , the sender compute instance may correspond tocompute instance 1030 and the destination compute instance maycorrespond to compute instance 610.

At 1310, the response packet is forwarded from a host machine hostingthe sender compute instance to an NVD associated with the host machine.The response packet may be communicated from the host machine using aNIC of the sender host machine.

At 1315, the NVD receiving the response packet may execute a VNIC (e.g.,a micro-VNIC) associated with the sender compute instance, which causesthe response packet to be communicated from the NVD to VNICaaS system.The packet be sent to an anycast IP address associated with VNICaaSsystem.

At 1320, the response packet directed to the VNICaaS system is receivedby top of rack (TOR) switch within the VNICaaS system.

At 1325, the TOR selects a particular VNICaaS host machine to processthe response packet from among multiple VNICaaS system host machines. At1330, a worker thread executed by the host machine selected in 1325 isselected for processing the response packet.

At 1335, the worker thread selected in 1330, based upon information inthe received packet determines an IP address to which the responsepacket is to be sent. The IP address determined may correspond to thephysical IP address of the NVD associated with the destination computeinstance to which the response packet is to be sent. For example, if theresponse packet is to be sent to compute instance 610 of FIG. 10 , thenthe determined IP address may correspond to the physical IP address ofNVD 606 that is associated with the compute instance 610 i.e., thedestination compute instance.

In certain implementations, the worker thread may use information storedin a flow table to determine the IP address in 1335. As described above,when a packet is sent from compute instance 610 to compute instance1030, the VNICaaS system may store information identifying the trafficflow corresponding to the packet and store state information for thenetwork flow, where the state information includes informationidentifying the physical IP address of NVD 606, information identifyingmicro-VNIC 604 associated with compute instance 610, and otherinformation. As part of the processing in 1335, the worker thread mayidentify a particular network traffic flow corresponding to the responsepacket, and then consult the flow table for this network traffic flowand access state information for the traffic flow. The state informationmay identify the physical IP address of NVD 606 and informationidentifying micro-VNIC 604.

At 1340, the response packet is forwarded from the VNICaaS system to thenetwork device associated with the IP address determined in 1335. Forexample, in FIG. 10 , the response packet may be communicated fromVNICaaS system 632 to NVD 606. As part of the processing in 1340, theworker thread encapsulates the response packet, and then a tunnelingprotocol is used to communicate the encapsulated response packet fromthe VNICaaS system to the destination NVD.

At 1345, the NVD receives the response packet from the VNICaaS systemand then forwards it to the destination compute instance. For example,in FIG. 10 , the response packet is forwarded by NVD 606 to computeinstance 610. As part of the processing in 1345, NVD 606 mayde-capsulate the response packet received from VNICaaS system 632 andthen forward it to compute instance 610.

As described above, in certain implementations, multiple service computeinstances may sit behind a single virtual IP address, such as the IPaddress associated with a load balancer fronting the service computeinstances. In such situations, in order to ensure that the combinationof the source IP address of the response packet and the source port ofthe response packet uniquely identifies the sending compute instance,VNICaaS system may perform port address translation (PAT) for the sourceport of the received response packet. For example, VNICaaS system maydetermine an ephemeral source port for the packet such that thecombination of the source IP address and the determined ephemeral sourceport uniquely identifies the sender of the response packet. The sourceport of the response packet is changed to the value of the determinedephemeral source port.

FIG. 14 depicts a diagram of an exemplary VNICaaS system. The VNICaaSsystem 1400 includes a TOR switch 1405, VNICaaS host machines 1410, andtwo service VNICs 1420 and 1430. It is appreciated that the VNICaaSsystem 1400 is intended to be illustrative and non-limiting.Specifically, the VNICaaS system 1400 may include more than two serviceVNICs. According to some embodiments, the VNICaaS system 1400 processesnetwork packets associated with different compute instances e.g.,compute instances associated with a customer's virtual network and/orcompute instances associated with a service's virtual network.

The TOR switch 1405 is connected to the VNICaaS host machines 1410. TheTOR switch 1405 receives packets that are forwarded to the VNICaaSsystem 1400 for packet processing. TOR switch 1405 is configured toselect, from the multiple VNICaaS host machines (that are available forpacket processing), a particular host machine for processing thereceived packet.

The host machine selected by the TOR switch is then responsible forfurther processing of the packet. Specifically, each host machinecomprises compute (e.g., one or multiple processors), storage (e.g.,system memory and storage), and networking resources that are availablefor packet processing performed by the host machine. In certainimplementations, a set of multiple processes or threads is configured oneach host machine for processing packets received by the host machine.Upon receiving a packet for processing from the TOR switch 1405, a hostmachine is configured to select an available worker thread, from the setof worker threads configured for that host machine, for processing thepacket. In certain implementations, the selected worker thread isconfigured to examine the received packet (e.g., one or more headers ofthe packet) and determine a service VNIC for processing the packet.

As shown in FIG. 14 , the service VNIC 1420 is selected to processpackets originating from two compute instances CI 1 and CI 2. Thecompute instance CI 1 is associated with micro-VNIC 10 whereas computeinstance CI 2 is associated with micro-VNIC 20. It is appreciated thatthe compute instances CI 1 and CI 2 may belong to the same customer VCNor different customer VCNs. Thus, the same service VNIC i.e., serviceVNIC 1420 is used to process packets received from different computeinstances. Additionally, the packets originating from the computeinstances CI 1 and CI 2 may be destined for service compute instanceswith a service VCN, respectively. For example, the packet originatingfrom compute instance CI 1 may be destined for service compute instanceSCI 50, and packets originating from compute instance CI 2 may bedestined for service compute instance SCI 60, wherein the servicecompute instances SCI 50 and SCI 60 may both reside in the service VCN.Additionally, service compute instance SCI 50 may be associated with amicro-VNIC 80, whereas service compute instance SCI 60 may be associatedwith micro-VNIC 90.

Each of the service compute instances (i.e., SCI 50 and SCI 60) may beconfigured to generate response packets to be delivered to therespective compute instances residing in the customer side VCN. Theresponses generated by each of the service compute instances may bedirected to the VNICaaS system 1400. As shown in FIG. 14 , within theVNICaaS system 1400, service VNIC 1430 is determined to the service VNICto process the response packets originating from the service computeinstances SCI 50 and SCI 60, respectively. The service VNIC 1430 is alsoreferred to herein as a reverse connection endpoint (RCE) service VNIC.It is noted that service VNIC 1430 may be hosted on VNICaaS system 1400in a similar manner as service VNIC 1420. Additionally, it isappreciated that although the compute instances CI 1 and CI 2 utilizedservice VNIC 1420 to transmit their respective packets to SCI 50 and SCI60, the response packets originating from SCI 50 and SCI 60 (andintended for CI 1 and CI 2, respectively) utilized service VNIC 1430. Inother words, response packets originating from a destination computeinstance (and intended for a source compute instance) may utilize adifferent service VNIC in the VNICaaS system 1400 than that used by thesource compute instance. Furthermore, it is noted that although in theabove description, the service compute instances are described as beingintended destinations for data packets originating from the computeinstances in the customer's VCN, the service compute instances (i.e.,SCI 50 and SCI 60) may also act as source compute instances for otherdata flows.

FIG. 15 depicts a simplified flowchart 1500 of processing packets usinga VNICaaS system according to certain embodiments. The processingdepicted in FIG. 15 may be implemented in software (e.g., code,instructions, program) executed by one or more processing units (e.g.,processors, cores) of the respective systems, using hardware, orcombinations thereof. The software may be stored on a non-transitorystorage medium (e.g., on a memory device). The method presented in FIG.15 and described below is intended to be illustrative and non-limiting.Although FIG. 15 depicts the various processing steps occurring in aparticular sequence or order, this is not intended to be limiting. Incertain alternative embodiments, the processing may be performed in somedifferent order or some steps may also be performed in parallel.Specifically, FIG. 15 depicts an example flow diagram of steps performedto process network packets from plurality of compute instances overVNICaaS system, according to at least one embodiment.

In the following description, reference is made to FIG. 7 to refer tothe plurality of compute instances. At 1505, a first compute instance(e.g., compute instance 610 in FIG. 7 ) on a first host machine (e.g.,host machine 614) originates a first packet to be communicated to afirst destination endpoint. A second compute instance (e.g., computeinstance 704) on a second host machine (e.g., host machine 710)originates a second packet to be communicated to a second destinationendpoint. The first and second compute instances may be part of a firstand a second subnet of a customer VCN.

At 1510, the first and second packets are received by a TOR switch(e.g., TOR switch 616 in FIG. 7 ) associated with a VNICaaS system.

At 1515, for each of the first packet and the second packet, the TORswitch uses a selection technique to select a particular host machinefrom multiple available host machines available in the VNICaaS systemfor processing the packet, and the first and second packets areforwarded to their respectively selected host machines. In certainimplementations, the TOR switch analyzes the first and second packetsand may use an ECMP technique to select the host machines for processingthe packets. The TOR switch may scan the headers of the first and secondpackets to identify transport protocols and type of packet flows of thepackets.

The first and second packets may be processed by the same host machineor by different host machines. For example, in one instance, the samehost machine may be selected for processing the first packet and thesecond packet. In another instance, a first host machine maybe selectedfor processing the first packet and a second host machine, differentfrom the first host machine, may be selected for processing the secondpacket.

For each host machine selected for processing the packet, at 1520, aworker thread is selected on the host machine for processing the packetreceived by that host machine. If the same host machine is selected forprocessing both the packets, the host machine may evenly distributeprocessing of packets across a set of worker threads executed by thathost machine. For example, a first worker thread may be selected forprocessing the first packet and a second worker thread may be selectedfor processing the second packet. In certain implementations, aReceiver-Side Scaling feature (RSS) feature within the host machine maydistribute first and second packets evenly between worker threads basedon a flow-hash algorithm.

At 1525, for each of the first and second packet, the worker threadselected for processing the packet selects a particular service VNIC forprocessing the packet. The selection of a service VNIC for a packet maybe based upon information contained in the packet. For example, incertain instances, the header information of a packet may identify asource VNIC (i.e., the VNIC associated with the compute instance thatsent the packet) for the packet. The worker thread may then determineand select a service VNIC that has been configured as being associatedwith the source VNIC. In certain instances, the service VNIC may beselected based upon destination information in the header of thepackets. For example, if the destination VNIC for a packet is a PE-VNICor a particular service VNIC, a particular service VNIC associated withthe PE-VNIC or service VNIC may be selected for processing the packet.

In certain instances, the same service VNIC may be selected in 1525 forprocessing both the first packet and the second packets. In otherinstances, different service VNICs may be selected for processing thefirst and second packets.

At 1530, for each of the first and the second packet, one or morepolicies specified for the service VNIC selected in 1525 for processingthe packet are determined.

At 1535, for each of the first packet and the second packet, based uponthe one or more policies associated with the service VNIC selected forprocessing the packet and further based upon the destination informationfor the packet as indicated in the header(s) of the packet, the workerthread processing the packet identifies a next hop target to which thepacket is to be sent.

At 1540, for each of the first packet and the second packet, the workerthread processing the packet causes the packet to be forwarded to thenext-hop target for the packet determined in 1535. The next-hop targetsfor the first and second packets may be same or different. The next-hoptarget to which a packet is sent in 1540 may be the destination of thepacket, or a next-hop that facilitates the communication of the packetto its intended final destination endpoint.

The VNICaaS system embodiments described in this disclosure provide fora scalable and highly available distributed infrastructure to processnetwork traffic. According to the teachings described herein, a packetis forwarded to the VNICaaS system, where a service VNIC is selected forprocessing the packet. Based upon the selected VNIC, the packet isprocessed and then forwarded to a next hop target to facilitatecommunication of the packet to its final intended destination. Thisoffloads VNIC-related forwarding functions from the NVDs to the VNICaaSsystem. The number of host machines in the VNICaaS system can be scaledup or down as desired to meet demand. For example, as the traffic (e.g.,the number of packets) communicated between compute instances increases,more host machines can be added to VNICaaS system to provide therequisite compute resources and bandwidth needed for processing theincreased volume of traffic without any degradation of performance.Further, since the NVDs now perform less processing, they do not need topossess the same level of resources (e.g., compute. memory, and networkresources) as in the past, thereby reducing their costs and the overallcost of the infrastructure.

In certain implementations, the same service VNIC may be associated withmultiple micro-VNICs (or regular VNICs) associated with multiple computeinstances. These compute instances may execute on the same host machineor different host machines. Further, the compute instances may belong tothe same customer VCN or different VCNs. In this manner, the sameservice VNIC is scaled to process packets received from multipledifferent compute instances.

On the VNICaaS system, a worker thread on a selected VNICaaS system hostmachine selects a service VNIC for processing a received packet and thenforwards the packet based upon the processing. A first packet receivedby the VNICaaS system may be forwarded to a first VNICaaS system hostmachine for processing, where a worker thread on the selected first hostmachine may select a first service VNIC for processing and forwardingthe first packet. A second packet received by the VNICaaS system may beforwarded to a second VNICaaS system host machine (different from thefirst host machine) for processing, where a worker thread on theselected second host machine may select the same first service VNIC forprocessing and forwarding the second packet. In this manner, the sameVNIC, namely, the first service VNIC is selected for processing twodifferent packets possibly originating from different compute instances.Additionally, different host machines in VNICaaS system may process thesame first service VNIC. Accordingly, the same service VNIC can beprocessed by different host machine in VNICaaS system.

In certain instances, processing performed by the VNICaaS system maydetermine that there are multiple possible next hop targets for apacket. A single service VNIC may thus identify multiple endpoints andassociated next hop targets. In such a situation, the VNICaaS system mayselect one of the multiple possible next hop targets. In this manner,the VNICaaS system may perform load balancing across the multiplepossible next hop targets.

A worker thread on a VNICaaS system host machine may also processmultiple service VNICs and process multiple packets from differentcompute instances. For example, a particular worker thread on a VNICaaSsystem host machine may be selected for processing a first packetreceived by the VNICaaS system from a first compute instance. Afterprocessing of the first packet by the particular worker thread iscompleted, the particular worker thread is available for processingother packets received by the VNICaaS system. For example, afterprocessing of the first packet is complete, the particular worker threadmay be selected for processing a second packet received by the VNICaaSsystem from a different compute instance than the first packet. Theparticular worker thread may select a different service VNIC forprocessing the second packet. After processing for the second packet iscompleted, the same particular worker thread may subsequently beselected for processing other packets. In this manner, the same workerthread may process packets from different compute instances usingdifferent service VNICs.

In certain implementations, upon receiving a packet, the VNICaaS systemperforms a hashing operation, wherein at least certain portions of thereceived packet are hashed in order to identify traffic flow informationassociated with the packet. By one embodiment, the VNICaaS system storesthe traffic flow information (associated with the packet) in a flowtable. The traffic flow information comprises state information relatedto the flow. Such state information is replicated and distributed to allhost machines included in the VNICaaS system. Accordingly, for aparticular traffic flow, a first packet of the traffic flow may beprocessed by a first host machine of the VNICaaS system, whereas asecond packet of the traffic flow may be processed by a second hostmachine of the VNICaaS system, which is different than the first hostmachine. Since the second host machine has access to the stateinformation of the particular traffic flow, the second host machine iscapable of processing packets of the particular traffic flow.

In certain implementations, a service VNIC included in the VNICaaSsystem provides for a load balancing functionality as described below.For example, consider the scenario in which a service VNIC (included inthe VNICaaS system) is associated with multiple micro-VNICS.Specifically, multiple micro-VNICS, each of which is associated with acorresponding compute instance, may send data that is processed by thesame service VNIC included in the VNICaaS system. In such a scenario,when the service VNIC is selected for processing a packet e.g., fromanother VNIC, the service VNIC may utilize certain algorithms todetermine one of the multiple micro-VNICs to which the data packet is tobe forwarded. Once the service VNIC identifies a particular micro VNICto which the packet is to be forwarded, the service VNIC may implement aselection techniques (such as a flavor of the ECMP algorithm e.g.,sticky ECMP) wherein subsequent packets belonging to the packet flow aredirected to the same micro-VNIC. In such a manner, the service VNIC maydistribute different flows amount different micro-VNICs to achieve aload balancing effect.

Example Cloud Infrastructure embodiment

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing. IaaS can be configured to provide virtualizedcomputing resources over a public network (e.g., the Internet). In anIaaS model, a cloud computing provider can host the infrastructurecomponents (e.g., servers, storage devices, network nodes (e.g.,hardware), deployment software, platform virtualization (e.g., ahypervisor layer), or the like). In some cases, an IaaS provider mayalso supply a variety of services to accompany those infrastructurecomponents (e.g., billing, monitoring, logging, security, load balancingand clustering, etc.). Thus, as these services may be policy-driven,IaaS users may be able to implement policies to drive load balancing tomaintain application availability and performance.

In some instances, IaaS customers may access resources and servicesthrough a wide area network (WAN), such as the Internet, and can use thecloud provider's services to install the remaining elements of anapplication stack. For example, the user can log in to the IaaS platformto create virtual machines (VMs), install operating systems (OSs) oneach VM, deploy middleware such as databases, create storage buckets forworkloads and backups, and even install enterprise software into thatVM. Customers can then use the provider's services to perform variousfunctions, including balancing network traffic, troubleshootingapplication issues, monitoring performance, managing disaster recovery,etc.

In most cases, a cloud computing model will require the participation ofa cloud provider. The cloud provider may, but need not be, a third-partyservice that specializes in providing (e.g., offering, renting, selling)IaaS. An entity might also opt to deploy a private cloud, becoming itsown provider of infrastructure services.

In some examples, IaaS deployment is the process of putting a newapplication, or a new version of an application, onto a preparedapplication server or the like. It may also include the process ofpreparing the server (e.g., installing libraries, daemons, etc.). Thisis often managed by the cloud provider, below the hypervisor layer(e.g., the servers, storage, network hardware, and virtualization).Thus, the customer may be responsible for handling (OS), middleware,and/or application deployment (e.g., on self-service virtual machines(e.g., that can be spun up on demand) or the like.

In some examples, IaaS provisioning may refer to acquiring computers orvirtual hosts for use, and even installing needed libraries or serviceson them. In most cases, deployment does not include provisioning, andthe provisioning may need to be performed first.

In some cases, there are two different challenges for IaaS provisioning.First, there is the initial challenge of provisioning the initial set ofinfrastructure before anything is running. Second, there is thechallenge of evolving the existing infrastructure (e.g., adding newservices, changing services, removing services, etc.) once everythinghas been provisioned. In some cases, these two challenges may beaddressed by enabling the configuration of the infrastructure to bedefined declaratively. In other words, the infrastructure (e.g., whatcomponents are needed and how they interact) can be defined by one ormore configuration files. Thus, the overall topology of theinfrastructure (e.g., what resources depend on which, and how they eachwork together) can be described declaratively. In some instances, oncethe topology is defined, a workflow can be generated that creates and/ormanages the different components described in the configuration files.

In some examples, an infrastructure may have many interconnectedelements. For example, there may be one or more virtual private clouds(VPCs) (e.g., a potentially on-demand pool of configurable and/or sharedcomputing resources), also known as a core network. In some examples,there may also be one or more security group rules provisioned to definehow the security of the network will be set up and one or more virtualmachines (VMs). Other infrastructure elements may also be provisioned,such as a load balancer, a database, or the like. As more and moreinfrastructure elements are desired and/or added, the infrastructure mayincrementally evolve.

In some instances, continuous deployment techniques may be employed toenable deployment of infrastructure code across various virtualcomputing environments. Additionally, the described techniques canenable infrastructure management within these environments. In someexamples, service teams can write code that is desired to be deployed toone or more, but often many, different production environments (e.g.,across various different geographic locations, sometimes spanning theentire world). However, in some examples, the infrastructure on whichthe code will be deployed must first be set up. In some instances, theprovisioning can be done manually, a provisioning tool may be utilizedto provision the resources, and/or deployment tools may be utilized todeploy the code once the infrastructure is provisioned.

FIG. 16 is a block diagram 1600 illustrating an example pattern of anIaaS architecture, according to at least one embodiment. Serviceoperators 1602 can be communicatively coupled to a secure host tenancy1604 that can include a virtual cloud network (VCN) 1606 and a securehost subnet 1608. In some examples, the service operators 1602 may beusing one or more client computing devices, which may be portablehandheld devices (e.g., an iPhone®, cellular telephone, an iPad®,computing tablet, a personal digital assistant (PDA)) or wearabledevices (e.g., a Google Glass® head mounted display), running softwaresuch as Microsoft Windows Mobile®, and/or a variety of mobile operatingsystems such as iOS, Windows Phone, Android, BlackBerry 8, Palm OS, andthe like, and being Internet, e-mail, short message service (SMS),Blackberry®, or other communication protocol enabled. Alternatively, theclient computing devices can be general purpose personal computersincluding, by way of example, personal computers and/or laptop computersrunning various versions of Microsoft Windows®, Apple Macintosh®, and/orLinux operating systems. The client computing devices can be workstationcomputers running any of a variety of commercially-available UNIX® orUNIX-like operating systems, including without limitation the variety ofGNU/Linux operating systems, such as for example, Google Chrome OS.Alternatively, or in addition, client computing devices may be any otherelectronic device, such as a thin-client computer, an Internet-enabledgaming system (e.g., a Microsoft Xbox gaming console with or without aKinect® gesture input device), and/or a personal messaging device,capable of communicating over a network that can access the VCN 1606and/or the Internet.

The VCN 1606 can include a local peering gateway (LPG) 1610 that can becommunicatively coupled to a secure shell (SSH) VCN 1612 via an LPG 1610contained in the SSH VCN 1612. The SSH VCN 1612 can include an SSHsubnet 1614, and the SSH VCN 1612 can be communicatively coupled to acontrol plane VCN 1616 via the LPG 1610 contained in the control planeVCN 1616. Also, the SSH VCN 1612 can be communicatively coupled to adata plane VCN 1618 via an LPG 1610. The control plane VCN 1616 and thedata plane VCN 1618 can be contained in a service tenancy 1619 that canbe owned and/or operated by the IaaS provider.

The control plane VCN 1616 can include a control plane demilitarizedzone (DMZ) tier 1620 that acts as a perimeter network (e.g., portions ofa corporate network between the corporate intranet and externalnetworks). The DMZ-based servers may have restricted responsibilitiesand help keep security breaches contained. Additionally, the DMZ tier1620 can include one or more load balancer (LB) subnet(s) 1622, acontrol plane app tier 1624 that can include app subnet(s) 1626, acontrol plane data tier 1628 that can include database (DB) subnet(s)1630 (e.g., frontend DB subnet(s) and/or backend DB subnet(s)). The LBsubnet(s) 1622 contained in the control plane DMZ tier 1620 can becommunicatively coupled to the app subnet(s) 1626 contained in thecontrol plane app tier 1624 and an Internet gateway 1634 that can becontained in the control plane VCN 1616, and the app subnet(s) 1626 canbe communicatively coupled to the DB subnet(s) 1630 contained in thecontrol plane data tier 1628 and a service gateway 1636 and a networkaddress translation (NAT) gateway 1638. The control plane VCN 1616 caninclude the service gateway 1636 and the NAT gateway 1638.

The control plane VCN 1616 can include a data plane mirror app tier 1640that can include app subnet(s) 1626. The app subnet(s) 1626 contained inthe data plane mirror app tier 1640 can include a virtual networkinterface controller (VNIC) 1642 that can execute a compute instance1644. The compute instance 1644 can communicatively couple the appsubnet(s) 1626 of the data plane mirror app tier 1640 to app subnet(s)1626 that can be contained in a data plane app tier 1646.

The data plane VCN 1618 can include the data plane app tier 1646, a dataplane DMZ tier 1648, and a data plane data tier 1650. The data plane DMZtier 1648 can include LB subnet(s) 1622 that can be communicativelycoupled to the app subnet(s) 1626 of the data plane app tier 1646 andthe Internet gateway 1634 of the data plane VCN 1618. The app subnet(s)1626 can be communicatively coupled to the service gateway 1636 of thedata plane VCN 1618 and the NAT gateway 1638 of the data plane VCN 1618.The data plane data tier 1650 can also include the DB subnet(s) 1630that can be communicatively coupled to the app subnet(s) 1626 of thedata plane app tier 1646.

The Internet gateway 1634 of the control plane VCN 1616 and of the dataplane VCN 1618 can be communicatively coupled to a metadata managementservice 1652 that can be communicatively coupled to public Internet1654. Public Internet 1654 can be communicatively coupled to the NATgateway 1638 of the control plane VCN 1616 and of the data plane VCN1618. The service gateway 1636 of the control plane VCN 1616 and of thedata plane VCN 1618 can be communicatively couple to cloud services1656.

In some examples, the service gateway 1636 of the control plane VCN 1616or of the data plane VCN 1618 can make application programming interface(API) calls to cloud services 1656 without going through public Internet1654. The API calls to cloud services 1656 from the service gateway 1636can be one-way: the service gateway 1636 can make API calls to cloudservices 1656, and cloud services 1656 can send requested data to theservice gateway 1636. But, cloud services 1656 may not initiate APIcalls to the service gateway 1636.

In some examples, the secure host tenancy 1604 can be directly connectedto the service tenancy 1619, which may be otherwise isolated. The securehost subnet 1608 can communicate with the SSH subnet 1614 through an LPG1610 that may enable two-way communication over an otherwise isolatedsystem. Connecting the secure host subnet 1608 to the SSH subnet 1614may give the secure host subnet 1608 access to other entities within theservice tenancy 1619.

The control plane VCN 1616 may allow users of the service tenancy 1619to set up or otherwise provision desired resources. Desired resourcesprovisioned in the control plane VCN 1616 may be deployed or otherwiseused in the data plane VCN 1618. In some examples, the control plane VCN1616 can be isolated from the data plane VCN 1618, and the data planemirror app tier 1640 of the control plane VCN 1616 can communicate withthe data plane app tier 1646 of the data plane VCN 1618 via VNICs 1642that can be contained in the data plane mirror app tier 1640 and thedata plane app tier 1646.

In some examples, users of the system, or customers, can make requests,for example create, read, update, or delete (CRUD) operations, throughpublic Internet 1654 that can communicate the requests to the metadatamanagement service 1652. The metadata management service 1652 cancommunicate the request to the control plane VCN 1616 through theInternet gateway 1634. The request can be received by the LB subnet(s)1622 contained in the control plane DMZ tier 1620. The LB subnet(s) 1622may determine that the request is valid, and in response to thisdetermination, the LB subnet(s) 1622 can transmit the request to appsubnet(s) 1626 contained in the control plane app tier 1624. If therequest is validated and requires a call to public Internet 1654, thecall to public Internet 1654 may be transmitted to the NAT gateway 1638that can make the call to public Internet 1654. Memory that may bedesired to be stored by the request can be stored in the DB subnet(s)1630.

In some examples, the data plane mirror app tier 1640 can facilitatedirect communication between the control plane VCN 1616 and the dataplane VCN 1618. For example, changes, updates, or other suitablemodifications to configuration may be desired to be applied to theresources contained in the data plane VCN 1618. Via a VNIC 1642, thecontrol plane VCN 1616 can directly communicate with, and can therebyexecute the changes, updates, or other suitable modifications toconfiguration to, resources contained in the data plane VCN 1618.

In some embodiments, the control plane VCN 1616 and the data plane VCN1618 can be contained in the service tenancy 1619. In this case, theuser, or the customer, of the system may not own or operate either thecontrol plane VCN 1616 or the data plane VCN 1618. Instead, the IaaSprovider may own or operate the control plane VCN 1616 and the dataplane VCN 1618, both of which may be contained in the service tenancy1619. This embodiment can enable isolation of networks that may preventusers or customers from interacting with other users', or othercustomers', resources. Also, this embodiment may allow users orcustomers of the system to store databases privately without needing torely on public Internet 1654, which may not have a desired level ofsecurity, for storage.

In other embodiments, the LB subnet(s) 1622 contained in the controlplane VCN 1616 can be configured to receive a signal from the servicegateway 1636. In this embodiment, the control plane VCN 1616 and thedata plane VCN 1618 may be configured to be called by a customer of theIaaS provider without calling public Internet 1654. Customers of theIaaS provider may desire this embodiment since database(s) that thecustomers use may be controlled by the IaaS provider and may be storedon the service tenancy 1619, which may be isolated from public Internet1654.

FIG. 17 is a block diagram 1700 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1702 (e.g. service operators 1602 of FIG. 16 ) can becommunicatively coupled to a secure host tenancy 1704 (e.g. the securehost tenancy 1604 of FIG. 16 ) that can include a virtual cloud network(VCN) 1706 (e.g. the VCN 1606 of FIG. 16 ) and a secure host subnet 1708(e.g. the secure host subnet 1608 of FIG. 16 ). The VCN 1706 can includea local peering gateway (LPG) 1710 (e.g. the LPG 1610 of FIG. 16 ) thatcan be communicatively coupled to a secure shell (SSH) VCN 1712 (e.g.the SSH VCN 1612 of FIG. 16 ) via an LPG 1710 contained in the SSH VCN1712. The SSH VCN 1712 can include an SSH subnet 1714 (e.g. the SSHsubnet 1614 of FIG. 16 ), and the SSH VCN 1712 can be communicativelycoupled to a control plane VCN 1716 (e.g. the control plane VCN 1616 ofFIG. 16 ) via an LPG 1710 contained in the control plane VCN 1716. Thecontrol plane VCN 1716 can be contained in a service tenancy 1719 (e.g.the service tenancy 1619 of FIG. 16 ), and the data plane VCN 1718 (e.g.the data plane VCN 1618 of FIG. 16 ) can be contained in a customertenancy 1721 that may be owned or operated by users, or customers, ofthe system.

The control plane VCN 1716 can include a control plane DMZ tier 1720(e.g. the control plane DMZ tier 1620 of FIG. 16 ) that can include LBsubnet(s) 1722 (e.g. LB subnet(s) 1622 of FIG. 16 ), a control plane apptier 1724 (e.g. the control plane app tier 1624 of FIG. 16 ) that caninclude app subnet(s) 1726 (e.g. app subnet(s) 1626 of FIG. 16 ), acontrol plane data tier 1728 (e.g. the control plane data tier 1628 ofFIG. 16 ) that can include database (DB) subnet(s) 1730 (e.g. similar toDB subnet(s) 1630 of FIG. 16 ). The LB subnet(s) 1722 contained in thecontrol plane DMZ tier 1720 can be communicatively coupled to the appsubnet(s) 1726 contained in the control plane app tier 1724 and anInternet gateway 1734 (e.g. the Internet gateway 1634 of FIG. 16 ) thatcan be contained in the control plane VCN 1716, and the app subnet(s)1726 can be communicatively coupled to the DB subnet(s) 1730 containedin the control plane data tier 1728 and a service gateway 1736 (e.g. theservice gateway of FIG. 16 ) and a network address translation (NAT)gateway 1738 (e.g. the NAT gateway 1638 of FIG. 16 ). The control planeVCN 1716 can include the service gateway 1736 and the NAT gateway 1738.

The control plane VCN 1716 can include a data plane mirror app tier 1740(e.g. the data plane mirror app tier 1640 of FIG. 16 ) that can includeapp subnet(s) 1726. The app subnet(s) 1726 contained in the data planemirror app tier 1740 can include a virtual network interface controller(VNIC) 1742 (e.g. the VNIC of 1642) that can execute a compute instance1744 (e.g. similar to the compute instance 1644 of FIG. 16 ). Thecompute instance 1744 can facilitate communication between the appsubnet(s) 1726 of the data plane mirror app tier 1740 and the appsubnet(s) 1726 that can be contained in a data plane app tier 1746 (e.g.the data plane app tier 1646 of FIG. 16 ) via the VNIC 1742 contained inthe data plane mirror app tier 1740 and the VNIC 1742 contained in thedata plane app tier 1746.

The Internet gateway 1734 contained in the control plane VCN 1716 can becommunicatively coupled to a metadata management service 1752 (e.g. themetadata management service 1652 of FIG. 16 ) that can becommunicatively coupled to public Internet 1754 (e.g. public Internet1654 of FIG. 16 ). Public Internet 1754 can be communicatively coupledto the NAT gateway 1738 contained in the control plane VCN 1716. Theservice gateway 1736 contained in the control plane VCN 1716 can becommunicatively couple to cloud services 1756 (e.g. cloud services 1656of FIG. 16 ).

In some examples, the data plane VCN 1718 can be contained in thecustomer tenancy 1721. In this case, the IaaS provider may provide thecontrol plane VCN 1716 for each customer, and the IaaS provider may, foreach customer, set up a unique compute instance 1744 that is containedin the service tenancy 1719. Each compute instance 1744 may allowcommunication between the control plane VCN 1716, contained in theservice tenancy 1719, and the data plane VCN 1718 that is contained inthe customer tenancy 1721. The compute instance 1744 may allow resourcesthat are provisioned in the control plane VCN 1716 that is contained inthe service tenancy 1719, to be deployed or otherwise used in the dataplane VCN 1718 that is contained in the customer tenancy 1721.

In other examples, the customer of the IaaS provider may have databasesthat live in the customer tenancy 1721. In this example, the controlplane VCN 1716 can include the data plane mirror app tier 1740 that caninclude app subnet(s) 1726. The data plane mirror app tier 1740 canreside in the data plane VCN 1718, but the data plane mirror app tier1740 may not live in the data plane VCN 1718. That is, the data planemirror app tier 1740 may have access to the customer tenancy 1721, butthe data plane mirror app tier 1740 may not exist in the data plane VCN1718 or be owned or operated by the customer of the IaaS provider. Thedata plane mirror app tier 1740 may be configured to make calls to thedata plane VCN 1718 but may not be configured to make calls to anyentity contained in the control plane VCN 1716. The customer may desireto deploy or otherwise use resources in the data plane VCN 1718 that areprovisioned in the control plane VCN 1716, and the data plane mirror apptier 1740 can facilitate the desired deployment, or other usage ofresources, of the customer.

In some embodiments, the customer of the IaaS provider can apply filtersto the data plane VCN 1718. In this embodiment, the customer candetermine what the data plane VCN 1718 can access, and the customer mayrestrict access to public Internet 1754 from the data plane VCN 1718.The IaaS provider may not be able to apply filters or otherwise controlaccess of the data plane VCN 1718 to any outside networks or databases.Applying filters and controls by the customer onto the data plane VCN1718, contained in the customer tenancy 1721, can help isolate the dataplane VCN 1718 from other customers and from public Internet 1754.

In some embodiments, cloud services 1756 can be called by the servicegateway 1736 to access services that may not exist on public Internet1754, on the control plane VCN 1716, or on the data plane VCN 1718. Theconnection between cloud services 1756 and the control plane VCN 1716 orthe data plane VCN 1718 may not be live or continuous. Cloud services1756 may exist on a different network owned or operated by the IaaSprovider. Cloud services 1756 may be configured to receive calls fromthe service gateway 1736 and may be configured to not receive calls frompublic Internet 1754. Some cloud services 1756 may be isolated fromother cloud services 1756, and the control plane VCN 1716 may beisolated from cloud services 1756 that may not be in the same region asthe control plane VCN 1716. For example, the control plane VCN 1716 maybe located in “Region 1,” and cloud service “Deployment 16,” may belocated in Region 1 and in “Region 2.” If a call to Deployment 16 ismade by the service gateway 1736 contained in the control plane VCN 1716located in Region 1, the call may be transmitted to Deployment 16 inRegion 1. In this example, the control plane VCN 1716, or Deployment 16in Region 1, may not be communicatively coupled to, or otherwise incommunication with, Deployment 16 in Region 2.

FIG. 18 is a block diagram 1800 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1802 (e.g. service operators 1602 of FIG. 16 ) can becommunicatively coupled to a secure host tenancy 1804 (e.g. the securehost tenancy 1604 of FIG. 16 ) that can include a virtual cloud network(VCN) 1806 (e.g. the VCN 1606 of FIG. 16 ) and a secure host subnet 1808(e.g. the secure host subnet 1608 of FIG. 16 ). The VCN 1806 can includean LPG 1810 (e.g. the LPG 1610 of FIG. 16 ) that can be communicativelycoupled to an SSH VCN 1812 (e.g. the SSH VCN 1612 of FIG. 16 ) via anLPG 1810 contained in the SSH VCN 1812. The SSH VCN 1812 can include anSSH subnet 1814 (e.g. the SSH subnet 1614 of FIG. 16 ), and the SSH VCN1812 can be communicatively coupled to a control plane VCN 1816 (e.g.the control plane VCN 1616 of FIG. 16 ) via an LPG 1810 contained in thecontrol plane VCN 1816 and to a data plane VCN 1818 (e.g. the data plane1618 of FIG. 16 ) via an LPG 1810 contained in the data plane VCN 1818.The control plane VCN 1816 and the data plane VCN 1818 can be containedin a service tenancy 1819 (e.g. the service tenancy 1619 of FIG. 16 ).

The control plane VCN 1816 can include a control plane DMZ tier 1820(e.g. the control plane DMZ tier 1620 of FIG. 16 ) that can include loadbalancer (LB) subnet(s) 1822 (e.g. LB subnet(s) 1622 of FIG. 16 ), acontrol plane app tier 1824 (e.g. the control plane app tier 1624 ofFIG. 16 ) that can include app subnet(s) 1826 (e.g. similar to appsubnet(s) 1626 of FIG. 16 ), a control plane data tier 1828 (e.g. thecontrol plane data tier 1628 of FIG. 16 ) that can include DB subnet(s)1830. The LB subnet(s) 1822 contained in the control plane DMZ tier 1820can be communicatively coupled to the app subnet(s) 1826 contained inthe control plane app tier 1824 and to an Internet gateway 1834 (e.g.the Internet gateway 1634 of FIG. 16 ) that can be contained in thecontrol plane VCN 1816, and the app subnet(s) 1826 can becommunicatively coupled to the DB subnet(s) 1830 contained in thecontrol plane data tier 1828 and to a service gateway 1836 (e.g. theservice gateway of FIG. 16 ) and a network address translation (NAT)gateway 1838 (e.g. the NAT gateway 1638 of FIG. 16 ). The control planeVCN 1816 can include the service gateway 1836 and the NAT gateway 1838.

The data plane VCN 1818 can include a data plane app tier 1846 (e.g. thedata plane app tier 1646 of FIG. 16 ), a data plane DMZ tier 1848 (e.g.the data plane DMZ tier 1648 of FIG. 16), and a data plane data tier1850 (e.g. the data plane data tier 1650 of FIG. 16 ). The data planeDMZ tier 1848 can include LB subnet(s) 1822 that can be communicativelycoupled to trusted app subnet(s) 1860 and untrusted app subnet(s) 1862of the data plane app tier 1846 and the Internet gateway 1834 containedin the data plane VCN 1818. The trusted app subnet(s) 1860 can becommunicatively coupled to the service gateway 1836 contained in thedata plane VCN 1818, the NAT gateway 1838 contained in the data planeVCN 1818, and DB subnet(s) 1830 contained in the data plane data tier1850. The untrusted app subnet(s) 1862 can be communicatively coupled tothe service gateway 1836 contained in the data plane VCN 1818 and DBsubnet(s) 1830 contained in the data plane data tier 1850. The dataplane data tier 1850 can include DB subnet(s) 1830 that can becommunicatively coupled to the service gateway 1836 contained in thedata plane VCN 1818.

The untrusted app subnet(s) 1862 can include one or more primary VNICs1864(1)-(N) that can be communicatively coupled to tenant virtualmachines (VMs) 1866(1)-(N). Each tenant VM 1866(1)-(N) can becommunicatively coupled to a respective app subnet 1867(1)-(N) that canbe contained in respective container egress VCNs 1868(1)-(N) that can becontained in respective customer tenancies 1870(1)-(N). Respectivesecondary VNICs 1872(1)-(N) can facilitate communication between theuntrusted app subnet(s) 1862 contained in the data plane VCN 1818 andthe app subnet contained in the container egress VCNs 1868(1)-(N). Eachcontainer egress VCNs 1868(1)-(N) can include a NAT gateway 1838 thatcan be communicatively coupled to public Internet 1854 (e.g. publicInternet 1654 of FIG. 16 ).

The Internet gateway 1834 contained in the control plane VCN 1816 andcontained in the data plane VCN 1818 can be communicatively coupled to ametadata management service 1852 (e.g. the metadata management system1652 of FIG. 16 ) that can be communicatively coupled to public Internet1854. Public Internet 1854 can be communicatively coupled to the NATgateway 1838 contained in the control plane VCN 1816 and contained inthe data plane VCN 1818. The service gateway 1836 contained in thecontrol plane VCN 1816 and contained in the data plane VCN 1818 can becommunicatively couple to cloud services 1856.

In some embodiments, the data plane VCN 1818 can be integrated withcustomer tenancies 1870. This integration can be useful or desirable forcustomers of the IaaS provider in some cases such as a case that maydesire support when executing code. The customer may provide code to runthat may be destructive, may communicate with other customer resources,or may otherwise cause undesirable effects. In response to this, theIaaS provider may determine whether to run code given to the IaaSprovider by the customer.

In some examples, the customer of the IaaS provider may grant temporarynetwork access to the IaaS provider and request a function to beattached to the data plane tier app 1846. Code to run the function maybe executed in the VMs 1866(1)-(N), and the code may not be configuredto run anywhere else on the data plane VCN 1818. Each VM 1866(1)-(N) maybe connected to one customer tenancy 1870. Respective containers1871(1)-(N) contained in the VMs 1866(1)-(N) may be configured to runthe code. In this case, there can be a dual isolation (e.g., thecontainers 1871(1)-(N) running code, where the containers 1871(1)-(N)may be contained in at least the VM 1866(1)-(N) that are contained inthe untrusted app subnet(s) 1862), which may help prevent incorrect orotherwise undesirable code from damaging the network of the IaaSprovider or from damaging a network of a different customer. Thecontainers 1871(1)-(N) may be communicatively coupled to the customertenancy 1870 and may be configured to transmit or receive data from thecustomer tenancy 1870. The containers 1871(1)-(N) may not be configuredto transmit or receive data from any other entity in the data plane VCN1818. Upon completion of running the code, the IaaS provider may kill orotherwise dispose of the containers 1871(1)-(N).

In some embodiments, the trusted app subnet(s) 1860 may run code thatmay be owned or operated by the IaaS provider. In this embodiment, thetrusted app subnet(s) 1860 may be communicatively coupled to the DBsubnet(s) 1830 and be configured to execute CRUD operations in the DBsubnet(s) 1830. The untrusted app subnet(s) 1862 may be communicativelycoupled to the DB subnet(s) 1830, but in this embodiment, the untrustedapp subnet(s) may be configured to execute read operations in the DBsubnet(s) 1830. The containers 1871(1)-(N) that can be contained in theVM 1866(1)-(N) of each customer and that may run code from the customermay not be communicatively coupled with the DB subnet(s) 1830.

In other embodiments, the control plane VCN 1816 and the data plane VCN1818 may not be directly communicatively coupled. In this embodiment,there may be no direct communication between the control plane VCN 1816and the data plane VCN 1818. However, communication can occur indirectlythrough at least one method. An LPG 1810 may be established by the IaaSprovider that can facilitate communication between the control plane VCN1816 and the data plane VCN 1818. In another example, the control planeVCN 1816 or the data plane VCN 1818 can make a call to cloud services1856 via the service gateway 1836. For example, a call to cloud services1856 from the control plane VCN 1816 can include a request for a servicethat can communicate with the data plane VCN 1818.

FIG. 19 is a block diagram 1900 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1902 (e.g. service operators 1602 of FIG. 16 ) can becommunicatively coupled to a secure host tenancy 1904 (e.g. the securehost tenancy 1604 of FIG. 16 ) that can include a virtual cloud network(VCN) 1906 (e.g. the VCN 1606 of FIG. 16 ) and a secure host subnet 1908(e.g. the secure host subnet 1608 of FIG. 16 ). The VCN 1906 can includean LPG 1910 (e.g. the LPG 1610 of FIG. 16 ) that can be communicativelycoupled to an SSH VCN 1912 (e.g. the SSH VCN 1612 of FIG. 16 ) via anLPG 1910 contained in the SSH VCN 1912. The SSH VCN 1912 can include anSSH subnet 1914 (e.g. the SSH subnet 1614 of FIG. 16 ), and the SSH VCN1912 can be communicatively coupled to a control plane VCN 1916 (e.g.the control plane VCN 1616 of FIG. 16 ) via an LPG 1910 contained in thecontrol plane VCN 1916 and to a data plane VCN 1918 (e.g. the data plane1618 of FIG. 16 ) via an LPG 1910 contained in the data plane VCN 1918.The control plane VCN 1916 and the data plane VCN 1918 can be containedin a service tenancy 1919 (e.g. the service tenancy 1619 of FIG. 16 ).

The control plane VCN 1916 can include a control plane DMZ tier 1920(e.g. the control plane DMZ tier 1620 of FIG. 16 ) that can include LBsubnet(s) 1922 (e.g. LB subnet(s) 1622 of FIG. 16 ), a control plane apptier 1924 (e.g. the control plane app tier 1624 of FIG. 16 ) that caninclude app subnet(s) 1926 (e.g. app subnet(s) 1626 of FIG. 16 ), acontrol plane data tier 1928 (e.g. the control plane data tier 1628 ofFIG. 16 ) that can include DB subnet(s) 1930 (e.g. DB subnet(s) 1830 ofFIG. 18 ). The LB subnet(s) 1922 contained in the control plane DMZ tier1920 can be communicatively coupled to the app subnet(s) 1926 containedin the control plane app tier 1924 and to an Internet gateway 1934 (e.g.the Internet gateway 1634 of FIG. 16 ) that can be contained in thecontrol plane VCN 1916, and the app subnet(s) 1926 can becommunicatively coupled to the DB subnet(s) 1930 contained in thecontrol plane data tier 1928 and to a service gateway 1936 (e.g. theservice gateway of FIG. 16 ) and a network address translation (NAT)gateway 1938 (e.g. the NAT gateway 1638 of FIG. 16 ). The control planeVCN 1916 can include the service gateway 1936 and the NAT gateway 1938.

The data plane VCN 1918 can include a data plane app tier 1946 (e.g. thedata plane app tier 1646 of FIG. 16 ), a data plane DMZ tier 1948 (e.g.the data plane DMZ tier 1648 of FIG. 16 ), and a data plane data tier1950 (e.g. the data plane data tier 1650 of FIG. 16 ). The data planeDMZ tier 1948 can include LB subnet(s) 1922 that can be communicativelycoupled to trusted app subnet(s) 1960 (e.g. trusted app subnet(s) 1860of FIG. 18 ) and untrusted app subnet(s) 1962 (e.g. untrusted appsubnet(s) 1862 of FIG. 18 ) of the data plane app tier 1946 and theInternet gateway 1934 contained in the data plane VCN 1918. The trustedapp subnet(s) 1960 can be communicatively coupled to the service gateway1936 contained in the data plane VCN 1918, the NAT gateway 1938contained in the data plane VCN 1918, and DB subnet(s) 1930 contained inthe data plane data tier 1950. The untrusted app subnet(s) 1962 can becommunicatively coupled to the service gateway 1936 contained in thedata plane VCN 1918 and DB subnet(s) 1930 contained in the data planedata tier 1950. The data plane data tier 1950 can include DB subnet(s)1930 that can be communicatively coupled to the service gateway 1936contained in the data plane VCN 1918.

The untrusted app subnet(s) 1962 can include primary VNICs 1964(1)-(N)that can be communicatively coupled to tenant virtual machines (VMs)1966(1)-(N) residing within the untrusted app subnet(s) 1962. Eachtenant VM 1966(1)-(N) can run code in a respective container1967(1)-(N), and be communicatively coupled to an app subnet 1926 thatcan be contained in a data plane app tier 1946 that can be contained ina container egress VCN 1968. Respective secondary VNICs 1972(1)-(N) canfacilitate communication between the untrusted app subnet(s) 1962contained in the data plane VCN 1918 and the app subnet contained in thecontainer egress VCN 1968. The container egress VCN can include a NATgateway 1938 that can be communicatively coupled to public Internet 1954(e.g. public Internet 1654 of FIG. 16 ).

The Internet gateway 1934 contained in the control plane VCN 1916 andcontained in the data plane VCN 1918 can be communicatively coupled to ametadata management service 1952 (e.g. the metadata management system1652 of FIG. 16 ) that can be communicatively coupled to public Internet1954. Public Internet 1954 can be communicatively coupled to the NATgateway 1938 contained in the control plane VCN 1916 and contained inthe data plane VCN 1918. The service gateway 1936 contained in thecontrol plane VCN 1916 and contained in the data plane VCN 1918 can becommunicatively couple to cloud services 1956.

In some examples, the pattern illustrated by the architecture of blockdiagram 1900 of FIG. 19 may be considered an exception to the patternillustrated by the architecture of block diagram 1800 of FIG. 18 and maybe desirable for a customer of the IaaS provider if the IaaS providercannot directly communicate with the customer (e.g., a disconnectedregion). The respective containers 1967(1)-(N) that are contained in theVMs 1966(1)-(N) for each customer can be accessed in real-time by thecustomer. The containers 1967(1)-(N) may be configured to make calls torespective secondary VNICs 1972(1)-(N) contained in app subnet(s) 1926of the data plane app tier 1946 that can be contained in the containeregress VCN 1968. The secondary VNICs 1972(1)-(N) can transmit the callsto the NAT gateway 1938 that may transmit the calls to public Internet1954. In this example, the containers 1967(1)-(N) that can be accessedin real-time by the customer can be isolated from the control plane VCN1916 and can be isolated from other entities contained in the data planeVCN 1918. The containers 1967(1)-(N) may also be isolated from resourcesfrom other customers.

In other examples, the customer can use the containers 1967(1)-(N) tocall cloud services 1956. In this example, the customer may run code inthe containers 1967(1)-(N) that requests a service from cloud services1956. The containers 1967(1)-(N) can transmit this request to thesecondary VNICs 1972(1)-(N) that can transmit the request to the NATgateway that can transmit the request to public Internet 1954. PublicInternet 1954 can transmit the request to LB subnet(s) 1922 contained inthe control plane VCN 1916 via the Internet gateway 1934. In response todetermining the request is valid, the LB subnet(s) can transmit therequest to app subnet(s) 1926 that can transmit the request to cloudservices 1956 via the service gateway 1936.

It should be appreciated that IaaS architectures 1600, 1700, 1800, 1900depicted in the figures may have other components than those depicted.Further, the embodiments shown in the figures are only some examples ofa cloud infrastructure system that may incorporate an embodiment of thedisclosure. In some other embodiments, the IaaS systems may have more orfewer components than shown in the figures, may combine two or morecomponents, or may have a different configuration or arrangement ofcomponents.

In certain embodiments, the IaaS systems described herein may include asuite of applications, middleware, and database service offerings thatare delivered to a customer in a self-service, subscription-based,elastically scalable, reliable, highly available, and secure manner. Anexample of such an IaaS system is the Oracle Cloud Infrastructure (OCI)provided by the present assignee.

FIG. 20 illustrates an example computer system 2000, in which variousembodiments may be implemented. The system 2000 may be used to implementany of the computer systems described above. As shown in the figure,computer system 2000 includes a processing unit 2004 that communicateswith a number of peripheral subsystems via a bus subsystem 2002. Theseperipheral subsystems may include a processing acceleration unit 2006,an I/O subsystem 2008, a storage subsystem 2018 and a communicationssubsystem 2024. Storage subsystem 2018 includes tangiblecomputer-readable storage media 2022 and a system memory 2010.

Bus subsystem 2002 provides a mechanism for letting the variouscomponents and subsystems of computer system 2000 communicate with eachother as intended. Although bus subsystem 2002 is shown schematically asa single bus, alternative embodiments of the bus subsystem may utilizemultiple buses. Bus subsystem 2002 may be any of several types of busstructures including a memory bus or memory controller, a peripheralbus, and a local bus using any of a variety of bus architectures. Forexample, such architectures may include an Industry StandardArchitecture (ISA) bus, Micro Channel Architecture (MCA) bus, EnhancedISA (EISA) bus, Video Electronics Standards Association (VESA) localbus, and Peripheral Component Interconnect (PCI) bus, which can beimplemented as a Mezzanine bus manufactured to the IEEE P1386.1standard.

Processing unit 2004, which can be implemented as one or more integratedcircuits (e.g., a conventional microprocessor or microcontroller),controls the operation of computer system 2000. One or more processorsmay be included in processing unit 2004. These processors may includesingle core or multicore processors. In certain embodiments, processingunit 2004 may be implemented as one or more independent processing units2032 and/or 2034 with single or multicore processors included in eachprocessing unit. In other embodiments, processing unit 2004 may also beimplemented as a quad-core processing unit formed by integrating twodual-core processors into a single chip.

In various embodiments, processing unit 2004 can execute a variety ofprograms in response to program code and can maintain multipleconcurrently executing programs or processes. At any given time, some orall of the program code to be executed can be resident in processor(s)2004 and/or in storage subsystem 2018. Through suitable programming,processor(s) 2004 can provide various functionalities described above.Computer system 2000 may additionally include a processing accelerationunit 2006, which can include a digital signal processor (DSP), aspecial-purpose processor, and/or the like.

I/O subsystem 2008 may include user interface input devices and userinterface output devices. User interface input devices may include akeyboard, pointing devices such as a mouse or trackball, a touchpad ortouch screen incorporated into a display, a scroll wheel, a click wheel,a dial, a button, a switch, a keypad, audio input devices with voicecommand recognition systems, microphones, and other types of inputdevices. User interface input devices may include, for example, motionsensing and/or gesture recognition devices such as the Microsoft Kinect®motion sensor that enables users to control and interact with an inputdevice, such as the Microsoft Xbox® 360 game controller, through anatural user interface using gestures and spoken commands. Userinterface input devices may also include eye gesture recognition devicessuch as the Google Glass® blink detector that detects eye activity(e.g., ‘blinking’ while taking pictures and/or making a menu selection)from users and transforms the eye gestures as input into an input device(e.g., Google Glass®). Additionally, user interface input devices mayinclude voice recognition sensing devices that enable users to interactwith voice recognition systems (e.g., Siri® navigator), through voicecommands.

User interface input devices may also include, without limitation, threedimensional (3D) mice, joysticks or pointing sticks, gamepads andgraphic tablets, and audio/visual devices such as speakers, digitalcameras, digital camcorders, portable media players, webcams, imagescanners, fingerprint scanners, barcode reader 3D scanners, 3D printers,laser rangefinders, and eye gaze tracking devices. Additionally, userinterface input devices may include, for example, medical imaging inputdevices such as computed tomography, magnetic resonance imaging,position emission tomography, medical ultrasonography devices. Userinterface input devices may also include, for example, audio inputdevices such as MIDI keyboards, digital musical instruments and thelike.

User interface output devices may include a display subsystem, indicatorlights, or non-visual displays such as audio output devices, etc. Thedisplay subsystem may be a cathode ray tube (CRT), a flat-panel device,such as that using a liquid crystal display (LCD) or plasma display, aprojection device, a touch screen, and the like. In general, use of theterm “output device” is intended to include all possible types ofdevices and mechanisms for outputting information from computer system2000 to a user or other computer. For example, user interface outputdevices may include, without limitation, a variety of display devicesthat visually convey text, graphics and audio/video information such asmonitors, printers, speakers, headphones, automotive navigation systems,plotters, voice output devices, and modems.

Computer system 2000 may comprise a storage subsystem 2018 thatcomprises software elements, shown as being currently located within asystem memory 2010. System memory 2010 may store program instructionsthat are loadable and executable on processing unit 2004, as well asdata generated during the execution of these programs.

Depending on the configuration and type of computer system 2000, systemmemory 2010 may be volatile (such as random access memory (RAM)) and/ornon-volatile (such as read-only memory (ROM), flash memory, etc.) TheRAM typically contains data and/or program modules that are immediatelyaccessible to and/or presently being operated and executed by processingunit 2004. In some implementations, system memory 2010 may includemultiple different types of memory, such as static random access memory(SRAM) or dynamic random access memory (DRAM). In some implementations,a basic input/output system (BIOS), containing the basic routines thathelp to transfer information between elements within computer system2000, such as during start-up, may typically be stored in the ROM. Byway of example, and not limitation, system memory 2010 also illustratesapplication programs 2012, which may include client applications, Webbrowsers, mid-tier applications, relational database management systems(RDBMS), etc., program data 2014, and an operating system 2016. By wayof example, operating system 2016 may include various versions ofMicrosoft Windows®, Apple Macintosh®, and/or Linux operating systems, avariety of commercially-available UNIX® or UNIX-like operating systems(including without limitation the variety of GNU/Linux operatingsystems, the Google Chrome® OS, and the like) and/or mobile operatingsystems such as iOS, Windows® Phone, Android® OS, BlackBerry® 20 OS, andPalm® OS operating systems.

Storage subsystem 2018 may also provide a tangible computer-readablestorage medium for storing the basic programming and data constructsthat provide the functionality of some embodiments. Software (programs,code modules, instructions) that when executed by a processor providethe functionality described above may be stored in storage subsystem2018. These software modules or instructions may be executed byprocessing unit 2004. Storage subsystem 2018 may also provide arepository for storing data used in accordance with the presentdisclosure.

Storage subsystem 2000 may also include a computer-readable storagemedia reader 2020 that can further be connected to computer-readablestorage media 2022. Together and, optionally, in combination with systemmemory 2010, computer-readable storage media 2022 may comprehensivelyrepresent remote, local, fixed, and/or removable storage devices plusstorage media for temporarily and/or more permanently containing,storing, transmitting, and retrieving computer-readable information.

Computer-readable storage media 2022 containing code, or portions ofcode, can also include any appropriate media known or used in the art,including storage media and communication media, such as but not limitedto, volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information. This can include tangible computer-readable storagemedia such as RAM, ROM, electronically erasable programmable ROM(EEPROM), flash memory or other memory technology, CD-ROM, digitalversatile disk (DVD), or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or other tangible computer readable media. This can also includenontangible computer-readable media, such as data signals, datatransmissions, or any other medium which can be used to transmit thedesired information and which can be accessed by computing system 2000.

By way of example, computer-readable storage media 2022 may include ahard disk drive that reads from or writes to non-removable, nonvolatilemagnetic media, a magnetic disk drive that reads from or writes to aremovable, nonvolatile magnetic disk, and an optical disk drive thatreads from or writes to a removable, nonvolatile optical disk such as aCD ROM, DVD, and Blu-Ray® disk, or other optical media.Computer-readable storage media 2022 may include, but is not limited to,Zip® drives, flash memory cards, universal serial bus (USB) flashdrives, secure digital (SD) cards, DVD disks, digital video tape, andthe like. Computer-readable storage media 2022 may also include,solid-state drives (SSD) based on non-volatile memory such asflash-memory based SSDs, enterprise flash drives, solid state ROM, andthe like, SSDs based on volatile memory such as solid state RAM, dynamicRAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, andhybrid SSDs that use a combination of DRAM and flash memory based SSDs.The disk drives and their associated computer-readable media may providenon-volatile storage of computer-readable instructions, data structures,program modules, and other data for computer system 2000.

Communications subsystem 2024 provides an interface to other computersystems and networks. Communications subsystem 2024 serves as aninterface for receiving data from and transmitting data to other systemsfrom computer system 2000. For example, communications subsystem 2024may enable computer system 2000 to connect to one or more devices viathe Internet. In some embodiments communications subsystem 2024 caninclude radio frequency (RF) transceiver components for accessingwireless voice and/or data networks (e.g., using cellular telephonetechnology, advanced data network technology, such as 3G, 4G or EDGE(enhanced data rates for global evolution), WiFi (IEEE 802.11 familystandards, or other mobile communication technologies, or anycombination thereof), global positioning system (GPS) receivercomponents, and/or other components. In some embodiments communicationssubsystem 2024 can provide wired network connectivity (e.g., Ethernet)in addition to or instead of a wireless interface.

In some embodiments, communications subsystem 2024 may also receiveinput communication in the form of structured and/or unstructured datafeeds 2026, event streams 2028, event updates 2030, and the like onbehalf of one or more users who may use computer system 2000.

By way of example, communications subsystem 2024 may be configured toreceive data feeds 2026 in real-time from users of social networksand/or other communication services such as Twitter® feeds, Facebook®updates, web feeds such as Rich Site Summary (RSS) feeds, and/orreal-time updates from one or more third party information sources.

Additionally, communications subsystem 2024 may also be configured toreceive data in the form of continuous data streams, which may includeevent streams 2028 of real-time events and/or event updates 2030 thatmay be continuous or unbounded in nature with no explicit end. Examplesof applications that generate continuous data may include, for example,sensor data applications, financial tickers, network performancemeasuring tools (e.g. network monitoring and traffic managementapplications), clickstream analysis tools, automobile trafficmonitoring, and the like.

Communications subsystem 2024 may also be configured to output thestructured and/or unstructured data feeds 2026, event streams 2028,event updates 2030, and the like to one or more databases that may be incommunication with one or more streaming data source computers coupledto computer system 2000.

Computer system 2000 can be one of various types, including a handheldportable device (e.g., an iPhone® cellular phone, an iPad® computingtablet, a PDA), a wearable device (e.g., a Google Glass® head mounteddisplay), a PC, a workstation, a mainframe, a kiosk, a server rack, orany other data processing system.

Due to the ever-changing nature of computers and networks, thedescription of computer system 2000 depicted in the figure is intendedonly as a specific example. Many other configurations having more orfewer components than the system depicted in the figure are possible.For example, customized hardware might also be used and/or particularelements might be implemented in hardware, firmware, software (includingapplets), or a combination. Further, connection to other computingdevices, such as network input/output devices, may be employed. Based onthe disclosure and teachings provided herein, a person of ordinary skillin the art will appreciate other ways and/or methods to implement thevarious embodiments.

Although specific embodiments have been described, variousmodifications, alterations, alternative constructions, and equivalentsare also encompassed within the scope of the disclosure. Embodiments arenot restricted to operation within certain specific data processingenvironments, but are free to operate within a plurality of dataprocessing environments. Additionally, although embodiments have beendescribed using a particular series of transactions and steps, it shouldbe apparent to those skilled in the art that the scope of the presentdisclosure is not limited to the described series of transactions andsteps. Various features and aspects of the above-described embodimentsmay be used individually or jointly.

Further, while embodiments have been described using a particularcombination of hardware and software, it should be recognized that othercombinations of hardware and software are also within the scope of thepresent disclosure. Embodiments may be implemented only in hardware, oronly in software, or using combinations thereof. The various processesdescribed herein can be implemented on the same processor or differentprocessors in any combination. Accordingly, where components or modulesare described as being configured to perform certain operations, suchconfiguration can be accomplished, e.g., by designing electroniccircuits to perform the operation, by programming programmableelectronic circuits (such as microprocessors) to perform the operation,or any combination thereof. Processes can communicate using a variety oftechniques including but not limited to conventional techniques forinter process communication, and different pairs of processes may usedifferent techniques, or the same pair of processes may use differenttechniques at different times.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that additions, subtractions, deletions, and other modificationsand changes may be made thereunto without departing from the broaderspirit and scope as set forth in the claims. Thus, although specificdisclosure embodiments have been described, these are not intended to belimiting. Various modifications and equivalents are within the scope ofthe following claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the disclosed embodiments (especially in thecontext of the following claims) are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (i.e., meaning“including, but not limited to,”) unless otherwise noted. The term“connected” is to be construed as partly or wholly contained within,attached to, or joined together, even if there is something intervening.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate embodiments and does not pose alimitation on the scope of the disclosure unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the disclosure.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is intended to be understoodwithin the context as used in general to present that an item, term,etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y,and/or Z). Thus, such disjunctive language is not generally intended to,and should not, imply that certain embodiments require at least one ofX, at least one of Y, or at least one of Z to each be present.

Preferred embodiments of this disclosure are described herein, includingthe best mode known for carrying out the disclosure. Variations of thosepreferred embodiments may become apparent to those of ordinary skill inthe art upon reading the foregoing description. Those of ordinary skillshould be able to employ such variations as appropriate and thedisclosure may be practiced otherwise than as specifically describedherein. Accordingly, this disclosure includes all modifications andequivalents of the subject matter recited in the claims appended heretoas permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the disclosure unless otherwise indicated herein.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein. In the foregoing specification, aspects of the disclosure aredescribed with reference to specific embodiments thereof, but thoseskilled in the art will recognize that the disclosure is not limitedthereto. Various features and aspects of the above-described disclosuremay be used individually or jointly. Further, embodiments can beutilized in any number of environments and applications beyond thosedescribed herein without departing from the broader spirit and scope ofthe specification. The specification and drawings are, accordingly, tobe regarded as illustrative rather than restrictive.

What is claimed:
 1. A method comprising: receiving, by a packetprocessing system comprising a plurality of host machines, a firstpacket originating from a source host machine that is different from theplurality of host machines, the packet processing system hosting aplurality of virtual network interface cards (VNICs); selecting, by thepacket processing system, a first host machine from the plurality ofhost machines for processing the first packet based on informationincluded in the first packet; identifying, by the first host machine andbased upon information included in the first packet, a first VNIC fromthe plurality of VNICs to be used for processing the first packet;determining, by the first host machine, a first next-hop target to whichthe first packet is to be forwarded based upon information associatedwith the first VNIC and destination information included in the firstpacket; and causing, by the first VNIC, the first packet to be forwardedto the first next-hop target.
 2. The method of claim 1, wherein thepacket processing system comprises a top-of-rack (TOR) switch that isconnected to each of the plurality of host machines, and wherein theselecting of the first host machine is performed by the TOR switch. 3.The method of claim 2, wherein the TOR selects the first host machine ofthe plurality of host machines using an Equal-Cost Multi-Path (ECMP)hash algorithm.
 4. The method of claim 1, further comprising: receiving,by a network virtualization device (NVD) associated with the source hostmachine, the first packet from the source host machine; andcommunicating, by the NVD, the first packet to the packet processingsystem comprising the plurality of host machines.
 5. The method of claim4, wherein the first packet is received by the NVD from a NetworkInterface Card (NIC) on the source host machine.
 6. The method of claim4, wherein the NVD comprises a processor, a memory coupled to theprocessor, and executes a packet processor configured to receive thefirst packet.
 7. The method of claim 4, wherein the first packetoriginates from a first compute instance hosted by the source hostmachine, wherein the first compute instance is part of a first virtualcloud network (VCN).
 8. The method of claim 7, wherein the communicatingcomprises: executing, by the NVD, a first micro-VNIC associated with thefirst compute instance and the first VNIC; and causing, by the firstmicro-VNIC, the first packet to be communicated to the packet processingsystem.
 9. The method of claim 1, wherein the first next-hop target isat least one of a VNIC, a service gateway, Dynamic Routing Gateway(DRG), an Internet Gateway, and a Network Address Translation (NAT)gateway.
 10. A packet processing system comprising: one or moreprocessors; and a memory including instructions that, when executed withthe one or more processors, cause the packet processing system to, atleast: receive, by the packet processing system comprising a pluralityof host machines, a first packet originating from a source host machinethat is different from the plurality of host machines, the packetprocessing system hosting a plurality of virtual network interface cards(VNICs); select, by the packet processing system, a first host machinefrom the plurality of host machines for processing the first packetbased on information included in the first packet; identify, by thefirst host machine and based upon information included in the firstpacket, a first VNIC from the plurality of VNICs to be used forprocessing the first packet; determine, by the first host machine, afirst next-hop target to which the first packet is to be forwarded basedupon information associated with the first VNIC and destinationinformation included in the first packet; and cause, by the first VNIC,the first packet to be forwarded to the first next-hop target.
 11. Thepacket processing system of claim 10, further comprising a top-of-rack(TOR) switch that is connected to each of the plurality of host machinesand selects the first host machine.
 12. The packet processing system ofclaim 11, wherein the TOR selects the first host machine of theplurality of host machines using an Equal-Cost Multi-Path (ECMP) hashalgorithm.
 13. The packet processing system of claim 10, furthercomprising: a network virtualization device (NVD) associated with thesource host machine, wherein the NVD receives the first packet from thesource host machine and communicates the first packet to the packetprocessing system comprising the plurality of host machines.
 14. Thepacket processing system of claim 13, wherein the first packetoriginates from a first compute instance hosted by the source hostmachine, and wherein the first compute instance is part of a firstvirtual cloud network (VCN).
 15. The packet processing system of claim14, wherein the NVD executes a first micro-VNIC associated with thefirst compute instance and the first VNIC, and wherein the firstmicro-VNIC causes the first packet to be communicated to the packetprocessing system.
 16. One or more computer readable non-transitorymedia storing computer-executable instructions that, when executed byone or more processors, cause: receiving, by a packet processing systemcomprising a plurality of host machines, a first packet originating froma source host machine that is different from the plurality of hostmachines, the packet processing system hosting a plurality of virtualnetwork interface cards (VNICs); selecting, by the packet processingsystem, a first host machine from the plurality of host machines forprocessing the first packet based on information included in the firstpacket; identifying, by the first host machine and based uponinformation included in the first packet, a first VNIC from theplurality of VNICs to be used for processing the first packet;determining, by the first host machine, a first next-hop target to whichthe first packet is to be forwarded based upon information associatedwith the first VNIC and destination information included in the firstpacket; and causing, by the first VNIC, the first packet to be forwardedto the first next-hop target.
 17. The one or more computer readablenon-transitory media storing computer-executable instructions of claim16, wherein the packet processing system comprises a top-of-rack (TOR)switch that is connected to each of the plurality of host machines, andwherein the selecting of the first host machine is performed by the TORswitch.
 18. The one or more computer readable non-transitory mediastoring computer-executable instructions of claim 17, wherein the TORselects the first host machine of the plurality of host machines usingan Equal-Cost Multi-Path (ECMP) hash algorithm.
 19. The one or morecomputer readable non-transitory media storing computer-executableinstructions of claim 16, further comprising instructions that, whenexecuted by one or more processors, cause: receiving, by a networkvirtualization device (NVD) associated with the source host machine, thefirst packet from the source host machine; and communicating, by theNVD, the first packet to the packet processing system comprising theplurality of host machines.
 20. The one or more computer readablenon-transitory media storing computer-executable instructions of claim19, wherein the first packet is received by the NVD from a NetworkInterface Card (NIC) on the source host machine.